What is the difference between a used-car salesman and a computer salesman?
The used-car salesman knows when he's lying to you!

Try again: What's the difference between a car salesman and a computer salesman?
The car salesman can probably drive!

Threefold

A computer salesman, a hardware engineer, and a software engineer are driving in a car together. Suddenly the right rear tire blows out, ahd the car rolls to a stop. Our three heroes pile out to investigate.

The salesman tsk-tsks sadly. "Time to buy a new car!" he announces.
Says the hardware engineer, "Well, first let's try swapping the front and rear tires, and see if that fixes it."
Replies the software engineer,"Naw, let's just try driving the car again, and maybe the problem will go away by itself."

A doctor, an engineer, and a programmer were debating what the world's oldest profession was (other than the obvious one)? The doctor said that medicine was the oldest because the Lord performed surgery in the removal of Adam's rib.

The engineer countered that before that act, the Lord had performed feats of engineering by creating the earth and heavens from nothing.

The doctor conceded that the engineer was right and that engineering was indeed the oldest profession.

But then the programmer interjected that programming was even older. He was chided by both the doctor and the engineer saying that engineering had to be the oldest, because before the Lord engineered the earth and heavens, there was nothing, only the Great Void, only Chaos! The programmer simply smiled and said: "Where do you think the Chaos came from? "

Truths

One of the main causes of the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs.''

--Robert Firth

How many software engineers does it take to change a lightbulb?

None: "We'll document it in the manual."

How many tech writers does it take to change a lightbulb?

None: "The user can work it out."

"All that was meant to bore you shitless."

- I. Goulden Combinatorics and Optimization 230