It’s hard but it’s not impossible. I like to think I’m smart enough to know which folk are just interested in the game and which are actually friendly towards me as a person. I also think I have a pretty good sense about who is ‘creepy’ and who isn’t.
Generally speaking, by the way, very few people are ‘creepy’. People are often different than the norm, but so are we (although arguably, not so much in today’s geek saturated culture). I try to always remember that whenever I talk to someone, especially as generally speaking I’m not that much different from them myself.