I've been meaning to talk on this for a long while, but today, it seems particularly relevant to me. Libertarian writer Megan McArdle, a few months back (emphasis mine):
But at the end of the day, when people are demanding that you do the impossible, your job is to explain why you can’t. The ability to manage the expectations of nontechnical users is actually an important piece of domain knowledge for technical people; if you flub that, you’ll fail just as surely as if you get the hardware or software wrong.
And, of course, on the other side, nontechnical stakeholders should make it their business to find out what is possible before, not after, they commit to designs and deadlines.So true, so true.