Its Always Sunny in Philadelphia is a great show. Both critics and regular television viewers agree that the show is very good, and an example that sitcoms can still be funny. For sitcoms, the reason they become unfunny is the need to keep characters the same for long runs of the show. Characters very rarely deviate from their beginning personalities. The straight man rarely becomes less straight during the show's run, the village idiot remains the village idiot, and the single girl remains single. It's Always Sunny, plays with the idea of characters that never change. Specifically, the characters in Its Always Sunny are terrible people. Dennis is a narcissistic, sexual predator, Dee is constantly seeking the attention of everyone around her because of her inflated ego, Mac is a homophobic and racist, Frank is an elderly former criminal, and Charlie is just stupid. Through 12 seasons, the characters have not adapted to the world around them, and actually damage almost everyone they have ever been in contact with. From lawyers, to priests, to wives every secondary character in the show has hide their lives ruined by contact with the gang, and the fact that the gang remains terrible people and get actively worse is what makes the show so good. The gang are terrible people who will never learn from their mistakes, and continue to get worse. Dennis and Dee were once, (and maybe still are) addicted to cocaine, and a repeating theme of an entire season is Mac being fat. The fact that the characters are so unlikable, spins them around the other side and makes them oddly endearing. Like you know these people are just caricatures, and that makes them interesting in a strange way. The character this has worked best for is no doubt Dee. At the start of the show's run, Dee was pretty much the decent one of the group. She was generally trusted to be above the others' schemes and antics. When Kaitlin Olsen wanted a larger part in the show as a member of the group, she slowly cracked and gave into the general madness of the group. Now she is one of the worst members, personality wise, of the group. The way It\s always Sunny keeps the gang from really changing in a positive way is through the toxic friendship that binds the gang together. In other shows, the main group is made up of friends that actually care about each other. The gang in It's Always Sunny are not friends. They are constantly in some form of competition to be the best of the bunch, usually by some shallow metric. The rare times when members have some form of decency, is when they are away from the larger group, and forced to deal with their problems head on. The reason It's Always Sunny is so deserving of praise is because it is able to use the standard tropes and format of a sitcom, to make the worst kinds of people likable for the audience.