A barhopping fellow, four sheets to the wind, stumbles into a bar and declares "I'm buying everyone in the bar a drink! Line 'em up, bartender!"
So the bartender pours everyone a drink, and frivolity commences until the bartender says to that first guy, "OK, that'll be $210."
The drunk guy says, "I don't have that kind of money!"
The bartender throws him out. A few minutes later, the drunk staggers back into the bar. This time he says, "I'm buying everyone in this bar a drink! Except for you bartender, when you drink, you get nasty."