Just realised, while in the shower. Three practitioners have told me, over the last 20 years, "You are very tense". The chiropractor, the herbalist, and the dentist. They were all looking at different things (slipped disc, varicose veins, teeth grinding making them sensitive). Odd that they all came to the same conclusion. Odd that I don't notice it most of the time. I blame my husband, of course.