What makes a movie ending great?

Is that sense of closure necessary? Do you enjoy it when filmmakers tease you with an open ending? Give some examples, if you can, so that we can all relate to it.

For example, I am particularly fond of the ending of Bicycle Thief (don’t watch if you’re worried about spoilers). I think it’s because the emotions of the characters are on high at the end, and I’m right there with them.