One of the guys in my church once said that if girls do anything that doesn't make sense to him, he just chalks it up as "a girl thing." At the time I took offense to that, but I'm realizing it's somewhat true, and it works as a great answer!
I now work in an environment where I am surrounded by guys. L, the only other girl here my age, is my life saver! We pretty much stick together and have one another's back. When one of us needs to make a head call, the other is always there to accompany (it's quite a hike over there - we are picky and prefer to use the one with running water - imagine that!). If one of us need to go to one of the other trailers nearby, the other usually tags along. Coffee runs, laundry drop off, a visit to the PX, you name it, and we do it together. The guys just don't understand it at all and like to tease us. I always just say "it's a girl thing." This morning, I had 3 bags of laundry (we bring our laundry into the office twice a week), so I took all kinds of flak for that! It's not my fault that I like my clothes clean, I'm a girl! The best, though, was this morning when L. beeped the horn so the guard at the gate would give us the go ahead... it turns out, the guy had been in the little port-a-john next to the guard house. When we got to the gate, he was laughing and so were we. The guy in the car with us thought it was totally unfair that the guard was laughing and not cursing us under his breath for beeping the horn. He was like "if it had been a guy, he would have been all mad." Hey, sometimes it pays to be a girl. =P