A man 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 the man that it appears that he has already had plenty of drinks, he could not be served additional liquor at this bar, and offers to call a cab for him.

A few minutes later, the same drunk stumbles in the side door of the bar.

The bartender comes over and, still politely but more firmly, refuses service to the man, and again calls a cab.

A few minutes later, the same drunk bursts in through the back door.

He orders a drink. The bartender comes over and emphatically reminds the man that he is clearly drunk, and will be served no drink, and either a cab or the police will be called immediately.

The surprised drunk looks at the bartender, and cries "Maaaan! How many bar do you work at?"