There's a guy at my LGS, who is contantly talking talking about himself, how much he knows about the game, what decks he has. Nobody listens, but he doesn't care and just keeps on talking. He constantly over explains the rules, when nobody asked. He brags that he knows every card. If you let him, he will ramble on about his manaless dredge EDH deck(it's terrible btw) or any of his other whacky never-seen-before deck builds for hours.
I picture every single poster in this thread as this guy.