I have noticed that I am less nervous in a super crowded bathroom. i used all mens rooms while at an airport, and each time the bathrooms were packed. With all of the men in there, no one even looked at me, I was even able to wash my STP, so much hussle to get in and get out left me unnoticed.
I feel more nervous when it is just one other person in there with me, cause I think they may say something.
Once while at college, I was washing my hands and this guy walked in, and murmored to himself "is this the wright bathroom" and checked the sign on the door (what a dick!) so I walked by him and left giving him a smug smile as he kinda mumbled "sorry"