Not just can, but do. (And perhaps that's the dividing line between frightening and nonfrightening fen...) And competitive, well, just competitive. Happens in all walks of life, all kinds of fannishness -- people who seem to have to establish some kind of hierarchy of who knows more or is better connected or has more rare items in a collection. Of course, this also speaks to me as a committed dilettante, knowing a little bit about as many things as possible, but not much about anything...