Back so soon?

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
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?