My ideal customer is: a girl who works at a cafe, or man at the counter with his girlfriend. They previous just utterly "get" it and the latter are polite without being threatening, order simply and regularly, nearly always tip a dollar to show off to their lady and to obey standard codes of chivalry, and are sympathetic even if they are alone ("this girl works behind a counter serving food, just like my girlfriend!"). Exception exception exception: the "Dairy King" at Chums.