You know a good ending when you see one. The Good, the Bad and the Ugly does not have a bad ending, nor an ugly one. It doesn’t actually have a good ending, either. It has a great ending, because calling it good would be an understatement. See also classics like Casablanca, Cinema Paradiso, The Godfather Part II, and The Shawshank Redemption, for reasons that are probably obvious if you’ve seen them.