First of all, they don't live with my cute, fun, stunningly gorgeous, and amazing in every way roommates.
They don't sit on the couch watching movies swooning over attractive people (like Matt Damon or Gilbert Blythe). They don't have dance parties to "Here in Your Arms" by Hellogoodbye in the kitchen at 9:30 in the morning while eating breakfast. They don't steal each other's clothes and try to put together the best outfit possible. They don't connive to leave two cute people alone together on the couch watching a movie. And after something cute happens, they don't giggle and scream and all get together and cuddle on one bed and hold hands with each other and talk and be ridiculous until 1 in the morning. All aspects of that are very important: the giggling, the screaming (even if it's groaning-screaming...it's still happy), the cuddling, the hand-holding. Also, acknowledging the fact while watching the movie, like Kate the other night: "I'm so glad we're girls! Guys don't do this!"
Also, fact, which has been proven over and over and over again by the fabulous girls in my apartment (both past and present) and which was once again proven TWICE this week: Not showering equals dating success.