I'm ambidextrous so it doesn't matter for me. But since I am, I tend to observe who is left and right handed around me since I'm pretty aware of ergonomic shift

I'm ambidextrous so it doesn't matter for me. But since I am, I tend to observe who is left and right handed around me since I'm pretty aware of ergonomic shifts between using either hand for certain activities. Out of left-handed people, around 80% use the mouse exclusively with their right hand. In fact I can only think of one other than you that exclusively uses the mouse with their left (a bookkeeper a few doors down from my office).