Anything over 15% should be because of extra service. All servers must report tips and tip out at end of there shift to the hostess, bartenders, bussers, plus the hourly rate of “next to nothing”. So if the bill is 400.00 the server still has to tip out on thier total sales,so, again.. 15% of 400$ is 60.00 so leaving less or god forbid nothing means the server still had to tip out, so She Paid to wait on the lousy tipper. Personally I tip 20% unless service truly sucked. Even then they get 15%.