Ever wonder why girls always go to the bathroom in groups? Example:
"I'm going to go to the bathroom, wanna come with me?"
Well, I've figured it out. They race. There are different kinds of races, such as duration, or speed. There is even evidence to believe that there is a scoreboard in their bathrooms. Even scorecards! Yes, scorecards, and guess where they keep them? In their purses. That's why they always bring their purses to the bathroom. Otherwise you could just show up in a bathroom and challenge someone but they won't believe that you're that fast if you don't have your scorecard! Anyone could claim to be the fastest bathroom-goer, right? Of course I am.
But then, there are rare occurrences in which one girl might go by herself. But, this can't be, it goes against the code! Well, to an extent... You see, when they go alone, they are merely practicing for the next time they have a friend to compete against. Yes, it should all make sense now.
As guys we tend to think in terms of competition. Girls? Not so much. It's why they're not so into sports for the most parts, or competition. The reason for the bathrooms I think shows a fundamental difference between most girls and guys. Girls think relationally. When they go to bathrooms together or to malls together it's not to accomplish a task but to build relationships. We think of shopping as "let's go, find what we came for, conquer the shopping task!" But with them shopping doesn't have to be just to get something, but to spend time with someone they want to get to know better. When a wife wants her husband to go to the store, he might think it's just a waste of time, but she wants to spend private time with him apart from all the kids and busy-ness.