How Number Four Got Her Name

Pamala's best guy friend is Dave. Dave lives with Mats (there are quite a few untold stories about these two that I've just realized should be written down for posterity. Bwahahaha...) and Jesse. One day Pamala was over at their house and she was complaining to Dave about Paula and how weird she was. Mats had only been half-paying attention when he suddenly perked up and said, "Wait, are you talking about Number Four?" Pamala was confused, but Mats often says odd things, so she was prepared to just continue. When Dave answered "Yes.", she became even more confused. And then it sunk in. "Oh my god, you named her Number Four?" They laughingly admitted that they had, in fact, christened Paula with the name Number Four.
Now, while this was initially amusing, Pamala quickly became a little worried about how extensive their numbering system was. After grilling them mercilessly, they were able to convince her that Paula was the only roommate with a number.
Apparently, Pamala, Orly and I all have some aspect of our selves that is memorable, that makes an impression that lasts past the first meeting. Paula...not so much. They could not remember much of anything about her, so they just started calling her "the fourth one", which quickly turned into Number Four.
Since Pamala, Orly and I had to live with her, we adopted this as a code name for her. We had many, many im conversations that consisted entirely of

Pamala: god i hate 4 soooooo much!!!
Sarah: i know shes so retarded!
Orly: At least she didn't flash you dorks!
All: shudder

Only with a lot more instances of how we hated her/how annoying she was/how weird she was. We even progressed so far as to refer to her by her code name in front of her. And her dumb ass never did figure it out. That we know of...