Every night, Joe would go down to the liquor store, get a six pack,
bring it home, and drink it while he watched TV.  One night, as he
finished his last beer, the doorbell rang.  He stumbled to the door
and found a six-foot cockroach standing there.  The bug grabbed him by
the collar and threw him across the room, then left.

The next night, after he finished his 4th beer, the doorbell rang.  He
walked slowly to the door and found the same six-foot cockroach
standing there.  The big bug punched him in the stomach, then left.

The next night, after he finished his 1st beer, the doorbell rang
again. The same six-foot cockroach was standing there.  This time, he
was kneed in the groin and hit behind the ear as he doubled over in
pain. Then the big bug left.

The fourth night Joe didn't drink at all.  The doorbell rang.  The
cockroach was standing there.  The bug beat the snot out of Joe and
left him in a heap on the living room floor.

The following day, Joe went to see his doctor.  He explained the
events of the preceding four nights.  "What can I do?" he pleaded.

"Not much" the doctor replied.  "There's just a nasty bug going
around."