Unpredictability and inconsistency of behavior are so bad for people in that group (and, really, everyone, they just can't work past it like a fraction of more

Unpredictability and inconsistency of behavior are so bad for people in that group (and, really, everyone, they just can't work past it like a fraction of more talented computer-users can). If opening something or performing an action ever doesn't do the thing it usually does—say, it presents some kind of modal or notice instead, as many programs do after updates or for other reasons—it'll completely derail them.