Because he never pays his debts.
or
The man says: "You go up there and tell him off. Go on, I'll hold your monkey for you."
or
Three:
One to write the light bulb removal program,
one to write the light bulb insertion program, and
one to act as a light bulb administrator to make sure nobody else tries to change the light bulb at the same time.
or
Five. One to screw it in and four to tell him how bitchin' he looked doing it.
or
Because an undocumented worker has been living on his head for the past 2 decades!
or