It depends, if my friend wants to talk about it (like maybe he/she wants to talk about the day at work), then i'll just listen and reply with short phrases. If it goes on forever, i'll just start talking about something else, but something i'd know they wanna talk about. But i'd never give fake laughs to friends, that's lame. If my friend happens to be talking about something i don't wanna talk about because it offends me, then i'd just tell em the truth.