"Principle Of Least Astonishment".
And, %@#@#&*! Google can't even define it. 🙁
Furthermore, ESR doesn't have it in the Jargon file...Time to write a web page, I guess. Or else, delete the thread entirely.
Ahh, here we go: http://en.wikipedia.org/wiki/Principle_of_least_astonishment
And it looks as if ESR calls it the "Rule Of Least Surprise".
POLA is strongly related to DTRT. IOW, you click on the "X", the window closes. Expected. If, however, you click on the "X" and your system reboots itself, that might well be classed as a POLA violation. Your firewall rsules say "pass such and so a packet", but your program logged that it's blocking packets based on the pass rule. WindowsXP reboots when a "BSOD" error errors. It not supposed to happen or not expected to happen, at least that what the average Joe with some concept of DTRT (do the right thing) would think....
The specific variant "POLA" may very well be a Unixism, and a BSD-specific one at that. Googling for P.O.L.A. site:freebsd.org produces 534 hits; at netbsd.org, about 55. Only one return from openbsd.org, and it's unrelated. In the Linux world, not much either. At kernel.org, 2 hits, both of which are quoting material from FreeBSD documentation. At linux.org, 2 hits, one is relevant. Of course, if the Penguin dudes call it "ROLS", that would explain those results.
So, no, you're definitely not stupid; blonde is often considered a good quality, and we like you around here, of course.
Apparently I was being just a little too, hmm, esoteric? 😉