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.
sounds like a good friend i wish i have a friend like you. haha
for me, i will just listen and it looks like respecting her. but if i am really not interested, i will find another topic? but it depends on the situation. if it is really really important, well i will just listen, if it's not really well then i'll have another topic or even just say 'okay. i see'. sometimes if i just say simple sentence, they will stop. but it is rude if you're always doing this. this is just for some time, not most of the time, you see. try to look interested, can you? good luck