Every group is consisted of a certain formula. Without the necessary parts needed, no posse can operate at maximum potential. I have composed an outline of the roles that are filled by each member of a posse, and why the filling of each of these roles is essential to said posse running smoothly. (This only applies to posses consisting of males. I am not going to pretend like I know anything about women.)
1. The destructive child. This is the idiot who breaks shit. Whether he's drunk as hell, on some sort of upper, or just not paying attention to where he's walking, shit is breaking. The destructive child also has other destructive tendencies. Generally this member of the posse is the most prone to fighting, often engaging in fisticuffs with random people over trivial issues such as how many beers he had in the fridge or which person's rep hockey team is the superior squad. Also, the destructive child's standards for women are considerably lower than anyone else in the group. Generally the destructive child will target an obviously inebriated women with little to no respect for herself. They will then move in on the targeted woman, berating her with insults and sexual innuendos. Somehow, despite the destructive child's startlingly rude attitude, shoddy attire and obvious disregard for personal hygiene, he will most likely stumble out of the bar with the mess of a woman, for a night of meaningless, regrettable sex. The destructive child is essential to the posse as he provides a thrill and sense of adventure to the rest of the group, daring them to best each other and themselves in ridiculousness each time the crew heads out.
2. The fat asshole. There's always an asshole, and generally, they are on the hefty side. The fat asshole is constantly condescending, confrontational and more times than not, drunk. Their drinking capacity is legendary (fat or not) and they never seem to care that they are the only one in the group pounding back a twelve pack of tall boys on a Wednesday afternoon. The fat asshole does not usually take well to insults or criticism, but can (and do) dish it out like it's nothing. This makes the other members of the group angry and fed up with the fat asshole from time to time, but the fact that he is just so fat and has had such a hard life makes it tough to stay mad at the kid. However, something awesome generally happens to the fat asshole every now and then for no good reason at all and you kind of ask yourself why the fuck you still hang around with this kid/ if there really is a God. The fat asshole is crucial to the operating of the posse as he provides an intimidating presence and always makes the other members of the group appear much better looking to women by comparison. Plus you all sort of feel like he's a good guy at heart, until he throws up in your car and then laughs at you as you clean it up.
3. The pushover. This is the kid that everyone constantly rips on. Ironically, he is usually the person that has everyone over to eat all his food and disrespect his furniture. The pushover is usually a good looking guy, with a steady job and a healthy, long-term relationship. He got solid grades all through school, whether he's still getting them or you've all graduated. Occasionally, the pushover will become fed up with the other members of the group calling his girlfriend a bitch and taking his cigarettes, and will explode into a "you fuckers take me for granted" rant. This will temporarily humble the other members of the group, who may lay off ripping on the pushover for a day or two. Then, the pushover will bail on poker night to go ice skating with his girlfriend, and again assumes the position of ridicule. The pushover is necessary to the posse as he provides the group with an outlet for them to direct their anguish and need to make fun of someone so that these things do not build up inside of them, possibly driving them to suicide.
4. The douchebag. This is the kid who's generally quiet, until he mucks half a bottle of Patron and heads to the clubs. He is the one that can convince the group to go to these awful clubs every now and then, where the other members of the group spend half an hour trying to get a beer, hear each other talk and watch their douchebag friend grind on some makeup plastered European looking girl. Generally, the douchebag friend is of some European descent himself, most likely Italian, Portuguese or Polish. When not in the clubs, the douchebag friend spends most of his time in the gym and at Subway, where he tries to promote a healthy-lifestyle image. He is always looking out for his boys, and has a humongous family ready to back his posse up if any of them might be in any serious trouble. He is crucial to the group as although he is at times embarrassing and seems to embody the opposite of everything you stand for, he is hilarious and comes with an undying sense of loyalty.
5. The mash-out friend. The kid who smoked a bit too pot in high school and still smokes his fair share. He is awesome because everything he does is done at an incredibly baked level and still done with relative ease and professionalism. Usually the mash-out friend will have a mash-out girlfriend, whom he hangs out with when the other friends go to the bars sometimes. He comes to the bars every now and then, but he's just not the partier that the rest of the members are. If you surveyed all of the members of the posse and asked which member they would hang out with one-on-one if they had to, they will all say the mash-out friend. This is because the mash-out friend is by far the least argumentative and confrontational of the group due to his tendencies to just not really give a fuck about anything. The mash-out friend is essential to the group because his forever-calm demeanor provides the group with a rock in the ups and downs of being boys. Whenever the posse may be pissy, the mash-out friend is always there to shed words of wisdom like "Dude, you guys are still pissed about that shit? Man..."
So there it is. If your posse exceeds five people, then you should make some cuts. Five is a solid number.