That, and fairly poor at reasoning. The main driver of tipping culture in our country is that the vast majority of states pay servers less than minimum wage (with even minimum wage putting you squarely below poverty level). Naming a tiny handful of states that do otherwise doesn't change that. As long as that is the case, setting all cultural norms of politeness aside, it is simply beyond the pale not to tip for good service. And if you happen to live in a state that pays minimum wage, I could be wrong but not tipping quite as much can be appropriate...last time I was in San Fran I was told by a server I didn't need to tip as much cause they are paid a decent hourly wage, although they are always appreciated, and the bigger the better as is always the case.