The refereeing is the single biggest problem the NBA faces right now - it's woefully inconsistent from ref to ref, game to game, and even play to play.
Fans tend to use bad reffing as an excuse when their team loses or struggles, and conveniently ignore bad calls that favor their own team, but when refereeing is bad it's a bad thing for the game in general, no matter who wins by what margin.
Bill Kennedy for example is an awful ref - even ignoring some of his questionable calls last night (haven't heard anyone mention the phantom offensive foul on Pierce in the 1st quarter yet; I replayed it 4 or 5 times on frame-by-frame and still couldn't figure out what was called), I've watched him referee several other games where I had no rooting interest, and he made multiple questionable calls and flat out blew others each time. And what's scary is he's far from alone, there are at least a half dozen other refs who are in the same boat. Even the refs that are pretty good in game have a tendency to get emotionally involved (Crawford) or make prima donna calls (Salvatore).
NBA refereeing is flatout a black eye on the league right now, whether it affects a game's outcome or not. Instant replay and YouTube is showing how embarrassingly off the refs are night after night, and the league doesn't seem to care enough to change it. I think that more than warrants complaining about it.