A man walks into the front door of a pub. He is obviously drunk, and staggers up to the bar, seats himself on a stool and, with a belch, asks the barman for a drink. The barman refuses to serve him stating he's already had far too much to drink but offers to call him a taxi. The drunk is briefly surprised, then softly scoffs, grumbles, climbs down off the bar stool and staggers out the front door.
Two minutes later, the same drunk stumbles in the SIDE door of the pub and wobbles up to the bar and hollers for a drink. The barman again politely but more firmly, refuses service to the man due to his inebriation, and again offers to call a taxi. The drunk looks at the barman for a moment angrily, curses, and shows himself out the side door, all the while grumbling and shaking his head.
Five minutes later, the same drunk bursts in through the BACK door of the pub, plops himself up on a bar stool, gathers his wits and belligerently orders a drink. The barman comes over and emphatically reminds the man that he is clearly drunk, will not be be served any drinks, and either a taxi the police will be called immediately.
The surprised drunk looks at the barman, and in hopeless anguish, cries "Man! How many pubs do you work at?"