"Bartender" joke

Roy walks into the front door of a bar. He is obviously drunk, and staggers up to the bar, seats himself on a stool and, with a belch, asks the bartender for a drink.

The bartender politely informs Roy that it appears that he has already had plenty to drink, he could not be served additional liquor at this bar, and could a cab be called for him?

Roy is briefly surprised, then softly scoffs, grumbles, climbs down off the bar stool and staggers out the front door.

A few minutes later, Roy stumbles in the SIDE door of the "same" bar. He wobbles up to the bar and hollers for a drink.

The bartender comes over and, still politely but more firmly, refuses service to him due to his inebriation, and again offers to call a cab. He looks at the bartender for a moment angrily, curses, and shows himself out the side door, all the while grumbling and shaking his head.

A few minutes later, Roy bursts in through the BACK door of the bar. He plops himself up on a bar stool, gathers his wits and belligerently orders a drink. The bartender comes over and emphatically reminds him that he is clearly drunk, will be served no drinks, and either a cab or the police will be called immediately.

Roy surprisingly looks at the bartender, and in hopeless anguish, cries - "MAAAN! How many bars do you work at!?!?!"