I've been a bartender for over 10 years if you had a big tab and forget to tip I always remembered the face.....but if you were a regular customer I would let it slide once or twice, after that I would normally say something....booze is a terrible thing...I've always noticed after years of being in the alcohol business...that if you act one way when your drunk at 21 or 22 you tend to keep those same traits, but to a lesser extent even when you get older...for example....if your a loud mouth, you'll always be a loud mouth...jm2c