I don't flirt because I am a bear. Bears love, honey ...
Here is one I read somewhere -
Person1: Do you know how much a polar bear weights?
Person2: No
Person1: Neither do I, but enough to break the ice.
The most important thing is the element of humour. Even if I want to make a friend, I always start off with some humour. It makes people comfortable. Unless the person doesn't value humour much .. but I would never approach such a person anyway.