Only Cool People Matter

Cool people are above normal people on the social hierarchy scale, to the point they can often be a Devil in Plain Sight. They can be mean and sometimes just plain vicious to non-cool people and the non-cools won't even bother to complain. After all, what's the point? If you're not cool, you're nobody.

Expect antagonists in works with this trope in effect to be cramping the hero's wicked cool style. They may also be evil. That's not the main issue. Style cramping is unforgivable.

This trope is a factor in Adults Are Useless. All adults are, by definition, non-cool.

Examples of Only Cool People Matter include:

Anime and Manga

Tengen Toppa Gurren Lagann: Kamina, hands down. Granted, the guy is good-natured, but also dumb as a post, borderline suicidal, and has a rep as a social delinquent in his own village. But the man is still Awesomebob McCool, because he has a really big drill at his disposal.

Film

The main difference between Rod and the other troopers in Super Troopers is that Rod is fat and dumb. He is, as a result, treated unapologetically as a Butt Monkey by the rest of the group. To their credit, the troopers at least try to justify their behavior by claiming that Rod is a bad person- although the only really "bad" thing he does is defect to the other troopers near the end of the movie who got his help by (get this) acting nice to him.
- Rod is also extemely aggressive and belligerent at one point nearly assaulting a fast food worker because he couldn't give him a "liter of cola". Also, as mentioned in the movie and later shown in the credits, he got into a fight with some schoolchildren.
This is used on the Alpha Bitch in Saved!, though this would appear to be a contradiction since the Alpha Bitch is, by definition, popular. No, in spite of being the most popular girl in the school she and her friends are still somehow too uncool to get dates.
This seems to be the case in Cloudy with a Chance of Meatballs, where Flint is an Acceptable Target in the town, although whether this is because he's a nerd or due to his many failed inventions is debatable. Brent certainly thinks that's the reason, since in one scene (after Flint has garnered some fame), Flint is let into a swanky restaurant while Brent is not, leading him to exclaim, "You're letting that guy in? But that guy's a nerd!"
Played with in Legally Blonde, where the protagonist, Elle, is high on the coolness scale, but she's also kind to the non-cools, helping several hopeless wrecks become fashionable and get cool boyfriends.
Inverting this trope is the whole point of Revenge of the Nerds. The titular nerds are the only ones that matter, and the popular people are either evil, or simply not important enough to matter if they become collateral damage. In either case, they are Acceptable Targets.

Literature

The derision and mockery Dick Grenville receives at the hands of his father in The King's General is largely due to this trope. Richard Grenville, after all, is The Ace, and simply oozes sheer manliness. So of course he's severely disappointed by his son who goes faint at the sight of blood. After the timeskip, Dick has become morose and deadpan about this state of affairs- not only does he know he's a disappointment, he also knows he'll never satisfy his father. He seems to have carried himself into the Royalist cause based on inertia alone.