It depends so much on the person. If it's with a friend, sure. But if there's the slightest hint that the person may have an interest in me I want to run away as fast as possible. And yes to the "mixed signals." I'm so careful, especially around guys, that I don't give off the slightest "flirty" signals.
Kissing is a bit weird. I've tried making out, once, just out of curiosity. It wasn't that great. So I guess I generally don't like them but in the right situation I could.