I've run into the very situation clavus mentions. Kind of the opposite of this thread, but a friend of mine went by his middle name as a kid and then started going by his first name once he was in college because going by his middle name was a pain. I met him after college, when he was going by his first name and was a coworker of mine. In walks some lady who goes "hi Andy!" and he quickly takes her into the back office to meet with her. The rest of us in the office were sitting there for the next half hour wondering wtf was going on and why that lady called him Andy
