Whatever you, personally, don't like.
Generic, definitionless insults like NPC are just the latest in a long and very boring line of non-insult that is just a roundabout way of saying "my opinions good, your opinions bad".
Poser, sheeple, etc. When you don't have an argument, why not just imply that the other side doesn't have real opinions and are just following trends, unlike your refined tastes. You like popular things too, of course, but when YOU do it its because you actually like that thing.
Its just bargain bin solipsism, without the self awareness.