this sounds like a few people I know or have known

from Joe Clark:

I reiterate my shibboleth about curmudgeons: Up people persons do not understand that curmudgeons are romantic and idealistic and, as a result, jaded and eternally disappointed. We know how well the world would work if we ran it, and we know how badly off it is now. The discrepancy frustrates us, inducing sarcasm and snappiness. Snark, essentially.