A few months ago, I wrote about how a new dancer devolved from a relaxed state to a nervous state.
www.gainesvilledance.com/Newsletters/Articles/tabid/79/Gainesville-Dance/188/Right-Now-You-Are-Perfect.aspx

When I first danced with her she was comfortable. Later, when I get back to her again, her fingers were instinctively grasping and she was off balance. This is what happened to her after only an hour of guys throwing her around and telling her what to do.

Last Sunday, Laura showed up late to Josh's West Coast Swing Dance.

When I started dancing with her she said, "You are pulling. You never pull."

She was right. I had not noticed I was pulling, could hardly tell I was doing it and could not stop.

This is what happens after three hours of West Coast Swing, despite six years of training. The mind seeks to save itself.