Three guys, a chemical engineer, an electrical engineer, and a computer engineer, are driving down the road together. All of a sudden the car dies. The chemical engineer says, "It must be something in the fuel system. We should check the fuel lines to make sure they're open." The electrical engineer says, "The problem must be electrical. What we need to do is check for loose wires." The computer engineer says, "You guys don't know anything about cars! All we have to do is get out and get back in again, that always works."
Three guys, a programmer, a hardware engineer and a computer salesman were driving down the road and their car suddenly dies. The programmer is clueless: "Looks like a hardware problem to me" he says. The hardware guy says "Maybe we could swap parts till it starts-up, then we'll know where the problem is." The sales guy says "You guys don't know anything about fixing things! All you do is turn it off and back on a couple of times, that always works."