Cause they work out.
None. They aren't about to change a bulb when flipping a switch has worked for 15 years.
The Internship
Cause everyone's dying to get in!
Cause it couldn't get on the right track. I made that joke when I was little and remembered it today, might as well post it.
Two. One to hold the bulb, and another to spin the story until the bulb fits.
They all fell off a truck.