So there is a game of favourites - that local is near-on a thousand bucks a year. Plus tips. So if I get the chance to start his drink the moment I see him out the window, I'll take it. You might wait an extra 30 seconds. The change he drops in the jar will probably add up to a car payment over a year.
I can easily imagine bars are a similar situation but more so. The regulars are probably spending a little more than $20 a week.