Another thing that annoys me is when the party doesn't make the waiter split the check, and everyone has cash except one person, who puts it on their card. I always have this fear that the person paying with their card isn't going to tip much. Some people I know tip in the 12% range, and some tip around 20%. I always fear that the credit card guy is the 12% guy, but I just gave him 120-125% of my bill. Being the credit card guy is pretty much always a great deal; the other diners will generally tip you more than they would the waiter, especially if it's a waiter and not a waitress.