Sarcasm not so nice , but it may indicate a challenge and that she is interested and she wants the guy to break down her resistance and make her heart melt , and if you can do that then you are " In like Flynn" ...lol
Humor is def attractive in a girl because it keeps the conversations going and allows you to have a good time. The thing I would tell you would be to let them know that you are like telling a joke by like smiling as you are saying it to let him know that it is a joke and to not be confused.
this is a really good question, actually it depends.. me and this one girl had such a great time we were laughing our whole date because I could make her laugh and she could make me laugh, we developed all theese little insiders, I know gay but whatever, and honestly she isn't funny like I don't know if she would be funny if I didn't like her and I don't know if my friends would think she is funny but I do so its weird and its def a turn on because I feel like we have a real stron connection,
sarcasm is a different kind of funny, if you can make them laugh its good as long as there not laughing at of politeness because overly sarcastic girls or guys get annoying.
Sense of humor is a great personality trait to have - I can handle pretty much every humor style out there, though it's a turn-off to me if anyone makes bitter or cynical jokes with frequent regularity.
No I want my girl never to laugh and be extremely dull.