I laugh if what she says is funny... enough said. I think it's hilarious when guys over do it. Like this one time(in band camp, LOL) my guy friend brought a girl to hang out with us during lunch. All she said was,"... Yeah I had bacon for breakfast." my friend started bellowing out the most obvious fake laugh I've ever heard. It was so obvious that the girl went," Is bacon funny to you? I don't get it. Why don't you explain the joke to me?" and he made up the stupidest explanation. This is it in his exact words," You see it's funny because when I went camping, my cousin and I caught a wild boar." and then he continues to make up crap. But then he ends the story with this jewel of an ending,"... and the entire experience reminded me of Brokeback Mountain." The girl looked at my friend and goes," OMG I had no idea you were gay. I'm so sorry for hitting on you." My other friend and I tried so hard to hold back our laughter but when she rounded the corner we were laughing so hard that I'm almost sure she heard us.
So the moral of the story is, NO! Don't force a laugh when talking to the girl you like.
I don't pretend she's funny because I like her. That's silly. Girls don't want to be put on a pedestal like that. If you pretend everything they do is perfect, they don't appreciate it when you are being genuine (because you always laugh, or you always say she's pretty).
I would say when you're with someone and in your own euphoria together, that because you like each other you might find what each other says to be more funny, or more intelligent, etc...And often that's not pretending, it's just you have a better understanding of your partner and know they're being silly. :P
Only if what she's saying is funny, or if they way she says it is humorous. If a girl has a knack for being unintentionally funny, that's the best of all. Girls that intentionally try to be funny, generally aren't.
Nope. I may laugh out of politeness if she said something that wasn't funny,or if it was funny then I would be. But usually that's not the case. It'd have to be a special case on how much I really cared.