How many bars?

A man walks into the front door of a bar. He is obviously drunk, and staggers up to the bar, seats him on a stool and, with a belch, asks the bartender for a drink. The Bartender politely informs the man 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? The drunk is briefly surprised, then softly scoffs, grumbles, climbs down off the bar stool and staggers out the front door.

A few minutes later, the same drunk stumbles in the SIDE door of the 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 the man due to his inebriation, and again offers to call a cab. The drunk 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, the same drunk 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 the man that he is clearly drunk, will be served no drinks, and either a cab or the police will be called immediately.

The surprised drunk looks at the bartender, and in hopeless Anguish, cries "MAAAN! How many bars do you work at?"