I'll object to the topic and list an ending I hate anyway because it contradicted everything the show had worked toward. I'm talking about the conclusion to Clannad After Story.
Spoiler for Clannad After Story:
The first problem with the ending is that it contradicts the sense of free will the series has presented with its characters. Every other arc in Clannad was concluded by someone's own hands while After Story's conclusion was an outside event. Supernatural forces existed prior but it was all on the characters; Fuko and the cat at the top of my head. Whatever sense of independence the series had built falls apart. Tomoya made the wish to go back in time but at no other point in the show did simply wishing make something so convenient.
Yet the biggest insult with the "reset" is that Tomoya's development was effectively a dream. What he remembers is moot if nobody else involved in how he changed recalls what had happened.
Was there any point in killing off Ushio? Honestly, the Illusory World shenanigans could have been removed and nothing of value is lost. Clannad After Story was seriously on the verge of communicating a
fantastic life lesson from episode 16 onward but didn't know when to stop with the drama.
By the way, if someone tells me the Visual Novel had a different message then thanks. It's always a good idea to bring "meta" material into discussion about an adaptation.
Yeah. I can't stand After Story's ending and by ending I mean pointlessly killing Ushio and all the shenanigans (I never get tired of that word) to follow.