After eating the in Lower East Side back in the early 1990s we left a tip but not a full 15% because the service was pretty lacking. The waiter chased us out of the restaurant yelling that we had to leave more. That it was "illegal" to tip as little as we did. My boyfriend at the time was pretty damn furious and it was only because we had to get somewhere that we didn't march back in an take the whole tip back