A businessman, a car mechanic and a computer engineer were all travelling in a car along a road that runs along the edge of a cliff face.  The driver starts driving down a steep hill, but when he tries the brakes nothing happens.  The car rapidly picks up speed as it descends towards the bottom of the hill, and it looks likely that they'll go right through the crash barrier, over the edge off the cliff and fall to their deaths.  Thinking quickly, the driver runs the car up along the side of the granite cliff, helping the reduce the speed of the car, and as he approaches the corner he applies the handbrake and wrenches the wheel to the right.  The back of the car skids out, but the driver somehow manages to correct the skid, swerves the car around the corner and brings the car to an abrupt halt.  Shaken, but not harmed in any way, all three get out of the car and survey the damage.

"Right" says the businessman.  "I think we need to have a meeting about this so that we can discuss what went wrong and try to come up with a solution to prevent a recurrence of the problem."

"Nah, talking's not gonna solve it" said the mechanic, who happened to be driving the car.  "I've got a boxfull of tools in the boot.  I'm gonna have a look at the entire braking system to see what's gone wrong with it so that I can isolate the fault and correct it."

And with that the computer engineer pipes up "I think you're both wrong!  I think we should push the car right up to the top of the hill and repeat the process to see if it crashes again!"