Cheeeaappppp, cheap, cheap, cheap; Cheeeeaappppp, cheap, cheap, cheap.
I was recently at the local pub/restaurant down the street from my office when one of the local leftist college professors complained because the bar tender served me first even though he was there first. The bartender's response: He's a better tipper.
The bottom line is that you are free to tip 10% if you want, but I wouldn't brag about it, nor would I complain if you get lousy service the next time you go back to that place. Also, don't complain the next time you go out to eat and an illegal Mexican is waiting on you because the owner of the place can't find legals willing to work for $3.85 per hour plus tips.