Sorry, but I can't directly answer those questions as I have a similar thing going on as well – I can be funny as hell, but usually only when in the right mood and when I'm relaxed with the person I'm talking with.

I think that's the important part – trying to be funny when you're not relaxed (i.e. first date) has too small of a chance to succeed. I don't know if this applies to jokes, since I'm more the over-the-top silliness sort of person who runs their mouth off.

Damn, is it me or have I just answered the question? If so, it was purely by accident.