The anime episode of the year in 2017 was episode 11 of Eromanga Sensei. Most of the Eromanga Sensei anime draws from books 1-3, but the final two episodes come from much later. Episode 12 was a scene in book 7 I believe, and now here we find episode 11 showing up in chapter 3 of book 8. Since the anime covered the material so perfectly, once I had verified that the anime was true to the book I didn't bother reading the rest of the way.
When I originally watched the anime I always had a lurking fear that episode 11 was an 'anime original' type story that was trying to wrap everything up nicely for the viewers. Clearly it was trying to wrap things up in just one season, but it was not an anime original. It was just skipping ahead to the juicy part in the actual novel series, for which no anime can be blamed. Who wouldn't want to animate the best scene in the series?
The only difference between the two is that in the book, Sagiri tells Masamune of their past connection, which leads Msamune to propose marriage to Sagiri on the spot. (Obviously Sagiri accepts because book 9 is titled 'Sagiri's new married life').
The anime, still mostly stuck in book 3's contents, clearly couldn't add that scene in. It would be out of place, there's still a lot of stuff that needs to happen first to get there. But the flashback can be introduced anywhere in the series because, after all, it's already happened. So I'm glad the anime gave us a flash forward to this flash back because boy was it good.
I still want to see a second season of Eromanga Sensei, but I have to admit all the funniest and best scenes have already been poached from their natural order in the first season which kept judiciously skipping ahead. So I doubt a second season would be able to live up to the glory of the first.
In similar style, the UQ Holder ova's just skipped ahead and covered any cool section of the manga they especially liked. The last ova came out recently, covering the hilarious day Touta took a truth serum drug and ran amok confessing to everyone he knows. Other great scenes covered by the ova's are the time Touta was trapped in the land of frozen time and his past with Yukihime, both very excellent moments to cover.
The ova's might actually be superior to the full tv season. If you're going to skip around randomly and not follow the correct continuity, you may as well do it full tilt like the ova's, rather than the half-assed manner the tv series attempted. Maybe the UQ Holder anime should have been a 'best-of' collection all along.
Eromanga Sensei's latest novel, volume 10, just came out today, so I hope the fan translator keeps working hard at this series and we don't fall any further behind.