When weighing the quality of a show, it comes down to its merits versus its demerits. But how should the two be weighed? Which has higher priority when it comes to the show's overall quality? Is it okay to have two or three terrible episodes if there are ten times as many tear-jerking ones? Can whole arcs be discarded with the sense that 'well this is just a small proportion of the whole, no big deal if it goes off the rails every now and then.'
This is a serious problem. For instance, just today, in the latest episode of Dragon Ball, Krillen suddenly became weaker than he was, literally, the very first time we met him. When he was like twelve years old, Krillen was tough enough that he could withstand machine gun volleys worth of bullets from Lunch. It never broke his skin or drew blood. Now, after he trained for decades and developed amazing ki to the point that even Frieza, even Cell had trouble dealing with Krillen, for the first time in the show, ever, a bullet pierced his skin and drew blood. Now, I don't care how little he's been training. He still maintains an active life as a police officer. There's no way a body full of that much power can regress that far. It's such a horrendous insult to Krillen to even write an episode like this. Even when he was fighting Frieza's henchmen in Ressurection of F, he was still a respectable warrior who could handle any number of lackeys. That means just a few weeks/months/maybe a year ago in the storyline, Krillen was at least as strong as he was when he landed on Namek. That was infinitely stronger than the start of the series, where he was already immune to bullets.
You simply cannot lose power that fast. In comparison, athletes like Michael Phelps have gone for years without any training, but come back and won gold medals at the next Rio Olympics, still the top of the world. If Michael Phelps can stay at the top of the swimming world without training for years, then Krillen could not possibly regress to pre-childhood levels of strength while maintaining an active life as a police officer.
When you reach such a ridiculous contradiction in the story, it's hard to swallow it and just say 'never mind, the previous two episodes were good.' A single bad episode that makes a mockery of the entire series and everything it stood for is not made up for by two good episodes previous to then. This is like saying 'a single act of adultery is no big deal, after all the previous two times my wife had sex it was with me.'
Which goes to the larger picture, in life, like in anime, a single evil act can negate everything good you did up until then. It can also negate anything good in life you do forever after, because it's not like the good you do can ever erase or undo the harm you did, or the metaphysical message you sent at that moment, which is, "I don't care about right and wrong, good or evil, the outside world is garbage to me and I'll treat it however I please, I'm just a feral beast beyond all reason, civilization and morals." Once you've said something like that, does it really matter if you donate to a children's hospital, or save some kids from a burning building? It doesn't change what you said at that moment. It doesn't change what remains at the core of your being, you're someone who, at any moment, could be just as amoral, ruthless and selfish as you were before, because if you were able to negate the feelings of everyone else on Earth before for your own momentary pleasure, what's to stop you from being willing to do it again?
Let's put it another way. If it's even remotely close in a person's inner balance scales between a marriage bond, love, your oath and honor, all of your precious memories, the harmony and stability of your home, the devastating pain you're going to cause your wife and children when they find out, knowing that from here on all of your relationships are just living a lie because they would never accept you if they knew, etc, etc, and a random fling with some nobody you met somewhere because hey, it seemed like fun and the mood swept you up in the moment -- then that means from the very beginning everything sacred and precious and valuable to you in your life was within the striking distance of a random fling. It means that from the very beginning, your entire life, you're the sort of person who never valued anything much more than a random fling. Or a hamburger. Or whatever the hell crosses your eyes. If a random, meaningless, temporary burst of pleasure is even possible, even capable, of even once outweighing the sacred in your heart, then you were no better than a filthy cur from the very beginning.
You may have kept up a good act for dozens of years, but now the truth of your heart is exposed. You're just a weak sniveling cur, whose fidelity to anything, to any principles, God, country, family, whatever, is no greater than the allure of a trip to Sonic. Onion rings and a cherry lime-aid > everything you stood for and everything you built up for your entire life.
I suppose there is some remote chance of redemption, of people improving from who they were in the past and becoming a different person entirely. But I suspect this happens very rarely, and there would have to be some physical break, some obvious tremendous change that occurs in a person's life, like they go meditate in the mountains for ten years, before I would ever take such lame testaments seriously. No one, after succumbing to such a feral instinct, after flouting and discarding all moral principles on Earth and everything they were taught since birth, can just 'shrug off' their evil deeds and promise to do better tomorrow.
Which brings us back to judging anime. If a truly atrocious episode airs, that simply destroys a character due to how awful their decisions are or how out of character what they're doing is, that doesn't just subtract say, one episode's worth of quality from the good ledger. It negates every good thing that character ever did in the entire story. It negates everything good that character might do for the rest of the story. It negates everything. Demerits are far more important than merits, because if a story was even capable of getting so bad, it obviously wasn't much good to begin with. In other words, if the author so misunderstands his characters and writes a plot so terribly that you begin to question what you ever thought you saw in these heroes and this chain of causality, then it's all lost. You haven't just set yourself back a few steps. You may as well just ball up the story and throw it in the trash can. Those characters are lost to the reader forever, they'll never be respected again. And the plot is ridiculous forever, it will never make sense again.
A character's actions in a story are just as significant as a living person's actions in the real world. If a hero does something unforgivably evil or stupid, you can never take them seriously again. They're instantly dismissed from your brain forever as beneath your notice. Likewise, if the consequences of an action in a story are the exact opposite of what all logic and reason demands they be, that is absolutely unforgivable. Because the central promise between an author and a reader is a mutual exploration of decisions and their consequences. If the consequences no longer have any relation to the decisions, the author has betrayed you. It's a bait and switch. He lured you into being interested in finding out the relative worth of a decision tree, and then just threw it all out and said "YOU'VE BEEN PUNKED!"
Just imagine if in Seiren, our main character had simply raped Tsuneki as she entered his room from the window wet and vulnerable in the middle of the night. And then Tsuneki had shrugged it off and said, oh well, I can understand how attractive I looked in those scanty clothes, how about I make you dinner tomorrow? If the story had simply proceeded along those lines, you would feel like this author is insane, that he's completely gone bonkers, that the entire story is some sort of surreal horror show instead of the romantic comedy it was billed as being.
There is no difference between making such a ludicrously bad choice when it comes to falling in love in a romantic comedy and Naruto's ludicrously bad choices during the 'meet the Akatsuki spy' arc. Pursuing Orochimaru when you and Sakura are already injured, Sai has switched sides, and Yamato isn't even on Kabuto's level, is batshit insane. Just straight out insane. Deciding to just jump into the middle of the enemy lair and not instead track them and ask for backup from Konoha is also absolutely insane. There was zero necessity. There was no imminent threat. All they had to do was keep Orochimaru in view and they could have brought in dozens of skilled jonin who actually had a chance at beating Orochimaru, instead of relying on Naruto who just seconds ago lost to him. Simultaneously, it was absolutely insane for Kabuto to heal Sakura, and for Orochimaru to spare Naruto and co by stopping Sasuke from killing them. And it was absolutely insane to not kill Kabuto when they had the chance, a known serial killer who has done untold damage to ninjas of Konoha, innocent test experiments he aided in the torture of (thousands of them!), and endless other civilians he's killed for whatever dubious ends. This is one of the worst people on Earth, and he's incredibly dangerous. He's a jonin on level with Kakashi, who becomes the next Hokage. He is bound only by a loose strip of wood, and is still fully capable of using his chakra. You just saw him beat the 5th Hokage in a fight a few years ago, and he's surely even stronger now than he was then.
The idea that you'd just leave a wood clone behind to look after him and consider him captured or eliminated as a threat is absolutely batshit insane. The idea that it's okay if he escapes is also absolutely batshit insane. There was no option in that moment except to kill Kabuto immediately. Any choice other than that is absolutely batshit insane.
If in Seiren the main character had raped Tsuneki in episode two, but that was okay because after all in episodes three and four they were really charming together, that would not make Seiren a good series. I fail to see why in Naruto it's okay for them to make equally totally dysfunctional choices and get away with it anyway, winning their fights just as ludicrously as in this hypothetical Seiren story he wins the girl.
Actually, there's more reason to believe raping Tsuneki in episode two would lead to a wonderful love life together from there on than that Naruto and Sakura would survive their foolhardy leap into Orochimaru's lair, or that Kabuto would be successfully taken prisoner via a few strands of wood and a wood clone. I can imagine an interesting love story that started with a rape, I could even see it somehow working out, and that it would actually become a magnificent masterpiece due to making it all flow together in an understandable manner. I can never understand the events in Naruto playing out as favorably as they actually did in the story. Even my hypothetical ridiculous scenario is not as ridiculous as what Naruto actually did.
How can stories be redeemed from irredeemably stupid scenes when real people in the real world are irredeemable when they do bad things? Why should there be a double standard? I guess the only answer is because it is convenient to overlook flaws in stories so that you can go on enjoying them. We are trying to be entertained here, so being too nitpicky just shuts you off from the opportunity to just ignore the obvious plot holes and just focus on the good moments. Whereas a bad person in the real world can still be used to design rockets or make millions or whatever, and therefore it is not unreasonable to continue dealing with them on a professional level, the 'profession' of a character or a story is to entertain you, and if they can continue doing so, it is not unwise to continue dealing with them and allowing yourself to be entertained.
So okay, let's say that for the sake of convenience, we can just ignore stupid Dragon Ball episodes like with Krillen, or stupid Naruto episodes where they don't kill Kabuto. Surely there must be some penalty, though? Some cognizance that no, this isn't acceptable? Some standards? If the proper weight of a demerit is 'immeasurable,' and it should actually cancel out the entire worth of the story, just to give us something to watch we have to be more merciful than that. Just to have something to do, we can't be so quick to discard every story we come across. So what is a more reasonable method of weighing demerits than the one that actually logically makes sense?
I would say that a story with a demerit cannot be better than a story without a demerit. I think that has to be the reasonable position. At the very least we cannot simply ignore the fact that this demerit exists. Okay, sure, we won't totally nullify your value. But there's no reason why we have to treat you with more respect than authors who carefully navigated their stories to never once betray themselves or their audience from beginning to end. Even this stance, which is being way too merciful, is enough to radically reconfigure my current anime rankings. And yet I cannot reasonably go on praising shows I know are riddled with not just slight flaws, but inconceivably enormous flaws that cannot possibly be explained away. Logic compels me to say that Kiki's Delivery Service, despite just being a short movie, is better than Naruto, which is nearing 500 episodes, because at least it has no flaws.