One of the things my friends and I find hilarious about this show is Cory and Shawn's relationship. This episode exemplifies what we think to the nth degree.
Shawn is dating a popular girl and true to his nature doesn't want to break up with her. The popular girl, being popular that she is, does not want to compete with anyone else. But, this is Shawn and he has a very important relationship with his best friend, Cory. They are so close and so tight that they will let nothing in get their way. The girlfriend is jealous that Shawn and Cory act like they're dating themselves. She tells Shawn the it's either her or Cory. It's pure Shawn when he doesn't want to chose and starts seeing Cory behind her back.
This episode is hilarious. Shawn and Cory act like they are a couple. It's become a slang term almost for us when we see two best friends of the same sex acting as close as they are knowing they are not a couple like that.