I recently read a book that I liked, but I felt that way about the ending.
The character gets himself into some pretty big political, personal, and emotional problems. And you think, how in the world will he solve all of this?
So he goes through all this stuff and at the end, basically passes out. When he wakes up, he finds out he won that immediate (main conflict). Then he asks, "Oh, wait, what about this other thing that was a problem?" And the people around him tell him, "Oh, someone else solved that while you were asleep!" And then he asks about another thing that was a big problem, and someone says, "Oh, turns out that was never actually a problem!" So everything gets resolved while he's unconscious and sort of just magically works out for him, all nice and tidy.
Everything was wrapped up, no loose ends, no nagging questions, no plot holes, but it wasn't really satisfying or believable. It was all a little too convenient.