A lot of people actually think they are weird, or at least give that impression, but really they are quite normal. There's just an innate desire to be an individual, so a lot of people think that they are "weird" if they like things that are slightly less mainstream.
For instance, if you play D&D or something RPG, you're really just geeky, not weird (unless you are Vin Diesel). If you write poetry and wear a lot of black, you are just a bit artsy (and probably pretentious), not weird. Etc.
So I've come up a list of traits and behaviors that I would consider actually weird based on people I've known and liked.