Lee, personally I don't know the difference between gaydar and wishful thinking, which is why I have learned to make no assumptions about sexual orientation and let it be revealed by the other person themselves in some unambiguous way. Placing myself in contexts in which it is reasonable to assume that many others around me are also gay or bi, such as in a gay bar or bookstore, is about the only way I know of to interact with others and not fear that I'm barking up the wrong tree.