Many women use two towels to dry themselves off because they need one for their body and one for their hair. Slacker and Steve say that if you're using two towels, then you're ruining the environment.
I use two towels. I have good reason to use two towels. I have very long, thick hair that you just can't wring all the water out of no matter how hard you try. It's like a separate being that sucks up as much water as it possibly can, to be completely honest. If I try to only use one towel, I end up with a wet towel by the time I'm trying to dry off whatever else is wet. Slacker and Steve may be saying that because you have to launder more towels, you're hurting the environment, but I wait until all my towels are dirty anyway so I can do a whole towel load. I also use my towels two or three times before I put them in the dirty clothes pile. Therefore, I'm doing a solid for the environment and I'm also using multiple towels.