It's the ET thing.

Anything where there's a small child who gets separated from his companion is an instant blub.

I'm an easy target, though. I'll bawl at anything.

With Moon, we only had one character to draw out all the emotion. There's a version where we see more of what happens... being careful not to give anything away here... after the end.

We even shot something, but it seemed so out of character with the rest of the film, we didn't use it.