When someone you're talking with starts to cry (and it isn't your fault), what do you do?

You’re talking with one or more friends, or you’re part of a group discussion (maybe including people you don’t know well), and you realize that someone is getting very emotional. This is personal to them and not because someone present said something distressing or hurtful. When they break into tears:

•  What do you think you should do?

•  What do you do? Is it the same thing or not?

•  Do you behave the same whether it’s a close friend or someone you hardly know?

•  What do you want someone else to do if you’re the person who starts to cry?