Copying mannerisms
I spent hours learning to emulate my English teachers smile.
His smile was one that always put me at ease, and being the one person in the whole school I trusted automatically, I thought it worth copying.
I also learned the wry, amused smile with which my PE teacher could disarm antagonism.
My English teachers smile got me into many interesting situations and my PE teachers smile got me out of some ugly ones.
The thing I think has allowed me the most extroversion is my Marfanoid build.
I think my height has let me overcome my timidity. I was average height for my class due to being jumped a grade, but when they slowed down I kept growing. The bullying stopped when I grew taller than them, but not until I got the wry smile working.
I find myself wondering how many of my facial mannerisms are unconsciously adopted masks,
which is a relevant consideration for me as I don't recognise facial features as much as movements.