The arthritic thumbs come from all the years of typing. In high school, mini-skirts were just coming into fashion so the rule there was that the hem had to touch the seat after you were on it on your knees. Some girls had terrible posture during those years (when the teacher didn't catch them bending down to make the skirts touch the seat
). We did have a typing teacher who many of us joked had either been a nun or gestapo before she came to teach us because of her constant barking to have our "wrists level--no slouching!"