"Serenity now"

I don't understand how some women can be so bitchy in what's supposed to be a relaxation class. I went to Pilates this morning, a few minutes before the class was supposed to start. There was hardly any room left, so I was left to set up my mat right next to the door. This women right next to me turns to me, almost immediately, and says "Do you think you could move your mat a bit? You're kind of close, and we do a lot of circles and rotations in this class."
(Let me take a moment to say that we had at least 2 feet between our mats)
Not wanting to make a scene, I simple said okay and proceeded to move my mat even closer to the door, making it virtually impossible for me to circle or rotate without hitting the cubbies filled with towels and shoes. But hey, at least she was no longer slightly inconvenienced.
If that wasn't enough, the woman continued to lecture me on what they do in the class, how they do it and how she needs a lot of space to do it ... as if I was some idiot first-timer who was only in the class to fulfill my New Year's resolution for a few weeks.
By the way, I've taken Pilates for months and certainly know the gist of it.
So I look her directly in the eyes and said, "Yeah, I know, I've been in this class before" before turning around and walking to the restroom. By the time I returned class had started, but the woman certainly made it clear that I was inconveniencing her workout by the way she was circling and rotating her legs ... despite the fact that I had given her more space than half the other people in the class had given each other. Because, you know, everybody else had manners.
I was in a sour mood the entire time, didn't concentrate very well and now I just feel annoyed. So much for inner peace. And common decency.