Who is "That Guy?"

I was watching Garden State last night. I haven't finished it yet. Garden State is obviously a pretty deep movie and this post isn't about that. It is about "that guy" that is in the movie. He is in almost every teen and twixter movie. When you watch a movie you can watch it as pure entertainment. Just a story. Or if it applies to your life in someway you empathize with a character. It always seems to be the main character or no character. Sometimes a movie just make you say "That is exactly how I feel" or "that is my life." No one is ever that guy in the corner smashing beer cans against his forehead. No, he is "that guy." Everyone always knows "that guy." I can name a million movies such as American Pie, Can't Hardly Wait, Dazed and Confused, or even Garden State. I always see a couple people who think, "Dang! I went to school with that guy!" I can be in a room full of people and they all seem to think that. No one ever looks at the "MILF guys, "Stifler," or "Beavis and Butthead" and goes..."Dude, THATS ME!!!" I have less than 5 hours til Interpol is onstage. Of course, I'll have a review of the show tomorrow.