Best and Worst Endings you've ever read

Damn! I hate Robin Hobb's Fitz series. That poor lad is simply Jon Snow, albeit better ending with continuation, but I hate how everyone treated him. 

best ending: life hunter. arimane blade is an amazing MC, i liked the magic system and the flow of the story, every forshadow has been answered and all the plot threads has been resolved. i was not disappointed at all.

worst ending: too many to choose from but i'd say it's usually the korean novels that tend to drop the ball when it comes to ending with chinese novels in a close second since they don't resolve all the plot threads and are just unsatisfying 

The Bartimaeus trilogy had a frustrating ending, and I'm obviously not going to explain why because that's a spoiler. Despite being an ending that I hated, however, it was a good ending. Funny how that works. 

Yeah, I didn't like the way it ended either. I wished some more happened, maybe the original MC coming to terms with life or the others, before it ended. I forgot what happened with Bartimaeus and the girl afterward, but I'm pretty sure they were working to reform the government and one other thing, so it wasn't the worst ending imo, but still not satisfying. It's like the end to the original Robin Hobb Fitz story. 

You said stories so I suppose these counts as well (I will just mention just one good ending and one bad ending):
Bad ending: Noblesse's ending because it is too rushed
Good ending: Hanma Baki's ending because it was simply good 

A monster who levels up. The ending was rushed, all those hype... for nothing. 

I really, really didn't like the Eragon ending 

Worst: I dunno if this counts because it’s not a novel but shokugeki no soma ended so anticlimactic and solved literally nothing. In fact, it ended in the middle of a battle and we didn’t even get to see the opponents dish nor how which one of them won.

Best: hard to say but... tensei slime? I must admit I didn’t read it (yet) but I skipped to the very last chapter because I wanted to see the absolute last sentence. Girl who ate a Death God has one of the best endings of the novel’s I’ve personally read. Truly a standout.