Due to their narcissistic absorption with themselves and each other, the Gang barely acknowledges the outside world, and often display a complete disregard for social norms. A recurring gag in the series is that the Gang will often become so caught up in their own world and focused on their own interests that they do not even notice anyone else and will often disregard and ignore the outside world completely until necessary, as part of a scheme or someone is forced to loudly interject. For example, the Gang frequently get caught up in a debate or argument at socially inappropriate times. Other examples include Frank, Dennis, Mac and Charlie attempting to break down a door, only to find the homeowners at home, and then proceed to break it down right in front of them anyway because of the lack of destructive gratification. On another occasion, Dennis and Charlie attempt to break through the door of a Korean restaurant by loudly kicking and ramming it, completely oblivious that they have disrupted the entire restaurant and the customers are staring at them.
The Gang has ended up causing much hardship to some of the people they come in contact with: Matthew Mara, a.k.a Rickety Cricket, was an ordained priest before an alleged "miracle" at Paddy's Pub("The Gang Exploits A Miracle")reintroduced him to the Gang, and soon he found himself in a downward spiral that reduced him to a homeless "street rat." Similarly, they have cost The Waitress her job("The Gang Sells Out")and subjected her to various other emotional trials and tribulations. They even cause trouble for people they don't actually know: while trying to "expose"Bruce Mathis as a "terrorist", they end up destroying a total stranger's car by ramming it with Frank's "rape van" multiple times.
Despite frequently wreaking havoc on the lives of virtually anyone who comes into contact with them, either selective memory , repression or general narcissism result in the Gang never seeming to remember any of it. Consequentially, they are often shocked when people they have hurt in the past are hostile towards them or do not want to help them.
No one in The Gang seems to have any friends outside The Gang. The creators of the show have often stated that one of the main reasons the characters stay with each other is because no one else will hang out with them. When Dennis inherits his mother's house and plans on using it as a "party mansion", everyone they think to invite is either dead or would have nothing to do with them because of something terrible The Gang has done to them.("Dennis and Dee's Mom Is Dead")Dee has to trick The Waitress into going out for a "Sex In The City" night with her by saying she will give her a notebook Charlie keeps on her if she does.("Who Pooped the Bed?")The Gang is forced to use Artemis as their sound person for a kid's pageant they put on even though she doesn't know what she's doing, because, as Mac says "We don't have a very deep bench".
Members of the gang often create alliances against each other, sometimes also allying with others:
Mac and Dennis vs. Frank and Cricket: Mac and Dennis hunt, despite Frank's warnings. Frank decides to join forces with Cricket to hunt Mac and Dennis back. ("Mac and Dennis: Manhunters")
Charlie and Dee: Charlie and Dee team up to find the source of Frank's meat, eventually deciding that it must be human meat. They bring a homeless guy back to Charlie's apartment, where they prepare to eat him. ("Mac and Dennis: Manhunters")
Dee and Dennis vs. Charlie and Mac vs. Frank: Dee and Dennis go undercover to find a serial killer, first using Dee as bait and then later deciding to pretend to kill The Waitress. Meanwhile, Frank tries to prove that the killer is Mac; Charlie fulfills his desire to become a lawyer by defending Mac against the accusations of the Gang. ("Mac Is a Serial Killer")
Every member of the Gang is tied to the Reynolds family, except for Mac. Mac did however bang Frank's ex-wife. In 10x08, Mac claims that he was adopted by Frank, however, this was likely so he would be allowed to participate.
The Gang all went to high school together (except for Frank).
Until 02x02, Mac and Charlie were not aware about Dennis' classification of their group as "The Gang". However, in The Gang Gets a New Member, the photos of the Gang and Schmitty had "The Gang" on the wall at the top.
Schmitty was the original fourth member of the gang and a roommate of Charlie's. Charlie despised Schmitty and eventually turned Mac and Dennis against him. Dennis kicked Schmitty out of a moving car and told him "You're out of the gang!" ("The Gang Gets a New Member")
The Gang has a ritual in which each member of The Gang gets a special day to themselves, during which everyone else must do exactly what they want them to do, without complaining (or else you get another day added on). The episode "Mac Day" takes us through a Mac Day, but we hear a bit about Charlie Day (which mostly involved hunting ghouls), and we see the beginning of Frank Day.