It seems that when I occasionally post over on RfM my alias is misinterpreted as indicating what I'm full of. It really doesn't bother me since I was raised in a very literalist Mormon household by a father who was a devout John Bircher and lover of unorthodox thinking. So I'm used to being an oddball and an outsider.
But that's not why I call myself Bull. That moniker was applied by one of my employees who loved giving everyone a nickname. The guy with allergy problems was Hack because he was constantly hacking up his phlegm. I became Bull when I showed up at work with a shaved head because I reminded him of the giant, shaved-headed bailiff on the TV show Night Court. I thought it beat the nickname I picked up in junior high (Jimmy, after the peanut farming former president) and I've used it ever since. The nickname probably fits in a number of other ways such as my physique and my direct approach toward handling problems.