You're fueling the problem with this tip crazy world. Instead of letting the kid learn a valuable lesson (that it's not a smart move to insult customers) you just let them continue on believing they're entitled to a tip. People like you are the reason there's a tip jar on every counter at every eatery.
I tip very well (20% minimum) when I receive good service (99% of the time). Not sure I'm the guy you want to stop wearing BYU gear. However, we might be better liked if the people who draw judgement on others based on something they posted on a fan board, stopped wearing BYU gear. Talk about self righteous.