The act of always complaining or otherwise being difficult is often called being cantankerous, though there isn't a direct noun for that. There are a few words

The act of always complaining or otherwise being difficult is often called being cantankerous, though there isn't a direct noun for that. There are a few words that might fit what you are looking for, of which I think the best is “curmudgeon”, and for lexical flexibility you can act curmudgeonly or be curmudgeonous. I'm not sure that curmudgeonous is a “real” word, spellcheckers refuse it and I rarely if ever see it elsewhere, but I like it as it essentially means the same as cantankerous but with less of a sharp edge - the difference between just naturally being difficult (curmudgeonous) and actively trying to be difficult (cantankerous). Both are often associated with older people more than younger, though in the fast moving world of tech you don't have to be very old to appear to have ancient views!