Some (not I) would speak of gratitude towards God, Fate, or a benevolent Universe. It is this sort of gratitude that is urged as a common virtue, along with platitudes /[everything happens for a reason|just go with the flow|it's all good|it was meant to be]/ and my personal favorite, It must have been written! The opposite tack, with its stubborn self-reliance, its sub rosa resentment of and hostility toward any suggestion of supernatural paternalism, is the one I here uphold; somewhat harder into the wind than mere skepticism. The ungrateful engineer does not merely look into the mouth of the horse found wandering in the dooryard; he rides it hard to town and back before giving it hay.

Ingratitude is not skepticism for the same reason that laziness is not forethought, impatience is not creativity, and hubris is not dignity. The last are virtues common to all; the former for programmers alone, maybe only programmers who write in a postmodern language. (There may be other specialists who benefit from these but I can't think who, right now, except perhaps the owner of a liquor store in a tough neighborhood.)

I endorse gratitude towards generous humans who design free tools that work unexpectedly well. Failing to say Thank You! when appropriate is mere boorishness and false ingratitude.