When you're acting and you need to cry, you want to put yourself in a position where you're trying not to cry, because that is generally what people try and do. They try to hold on to their emotions, they don't want to lose them.
I do so many things. Like when I was younger, if I drove past a house that I didn't want to live in, I'd hold my breath. Driving around somewhere like Slough I'd go blue in the face.