Two little anecdotes illustrate the point of our title.
Anecdote 1:
I’m at work and one of the geeks and I are playing around with a Dell laptop running Mandrake Linux 10 and trying to get its display output to a VGA projector. This should be trivial, but it wasn’t. I readily acknowledge that I don’t know shit about laptops and this guy does. But as he’s struggling and fumbling around for minutes after minute, I say, hey maybe it wants to be rebooted. No, he says, that’s not it. More minutes go by before he tries rebooting. Bingo.
Anecdote 2:
A client for whom I do web development emails me a spreadsheet in which there is a column of numbers that is supposed to match id numbers in a database table. I start fooling with the sorting and unwittingly commit the most bone-headed mistake any fool who knows spreadsheets knows not to do:  I highlight a column and say “sort..,” and when the dialogue pops up and prompts me to “widen the selection” I say, “bah, I know what I’m doing” and bypass it, and fail to notice that it sorted only the values in that column and left the rest untouched. Being a database guy used to saying “select * from some_table order by foo,” I suppose I just expect all the data fields in a row to stay together. But no excuses — I continue to examine this spreadsheet, see the ids have apparently been randomly re-assigned, and start mentally accusing the clueless ones of somehow screwing something up, and proceed to waste numerous minutes of their time with emails trying to encourage them to get it right, because they don’t know shit, and I do. Uh huh.