"I liked/watched/read/played X before it was cool or popular!" Fuck off with your hipster shit! No one cares! The book, game, comic, movie, or show was not just made for "you" in mind. Stop trying to act like your "with it" (look cool), because it's impossible to be on top or with everything.
"X is not good because Y people latched on to it!" No! Don't start! You can still enjoy the whatever despite whoever else is enjoying it.
Just joking, kidding, or just a prank bro. People like that are narcissistic douche bags.
"If everyone did this or jumped off a bridge, would you?"That shit is usually used for closing argument someone can't win or does not want to debate, despite the person starting the argument is eager to close it early.
"This is how we do it in [insert city, town, state, country, or continent!]". Congragu-fucking-lations, you are not in home whatever anymore and completely different place with values, ethics, and rules. They may be right, they may be wrong. Either way, does not give you to the right to act like a socially retarded asshole or insensitive jerk off that knows better than everyone else.