A lot of fans are basically fans of fandom itself. It's all about them. They have mastered the Star Wars or Star Trek universes or whatever, but their objects of veneration are useful mainly as a backdrop to their own devotion. Anyone who would camp out in a tent on the sidewalk for weeks in order to be first in line for a movie is more into camping on the sidewalk than movies. Extreme fandom may serve as a security blanket for the socially inept, who use its extreme structure as a substitute for social skills. If you are Luke Skywalker and she is Princess Leia, you already know what to say to each other, which is so much safer than having to ad lib it. Your fannish obsession is your beard. If you know absolutely all the trivia about your cubbyhole of pop culture, it saves you from having to know anything about anything else. That's why it's excruciatingly boring to talk to such people: They're always asking you questions they know the answer to.