If it seems to be an incredibly stupid username, I usually check their profile, to see if the strange suspiscion that I suddenly feel is truth. I try to be unbiased and not given to prejudice or manufactured opinions, so I read through the profile and see what they have posted, and how they have reacted. In this way, I may have an arousing suspiscion about them, but I don't immediately judge them based upon such things.

Really, it's just like the real world. Some people may, from their physical appearence, seem to be something, but in the end, they are different from what you first pictured them as.