I Don't Know Much Science But....
One of things I learned from living with 10 plus roommates (not all at the same time--it was the Dollhouse, not the Frat House) is that the bathroom can become one of the most complicated places in the home--especially if you share the same social life... And even though now it is just me and the husbear--we still have to duck and dodge around each other when it comes to the morning routine--and here is my favorite weapon in that arsenal.
Did you know that you can use a small amount of this old school shaving cream on your mirror and keep it from foggy up from multiple showers? I don't claim to understand the science but it really does the trick when you have to shave, do makeup or just get dressed in a hurry--no time to wait for the room to defog. It's probably my best grooming secret and can be a huge help when on the go!