Told by Gerald Weinberg in various incarnations:

A group of ten top software engineers is sent to a class for aspiring managers. The teacher walks in and asks this question:

"You work for a software company which develops avionics (software that controls the instruments of an airplane). One day you are taking a business trip. As you get on the plane you see a plaque that says this plane is using a beta of the software your team developed. Who would get off?"

Nine developers raised their hands. The teacher looked at the tenth and asked, "Why would you stay on?"

The tenth said, "if my team wrote the software, the plane would not get off the ground, much less crash."