My school unironically thought this. I was left handed as a kid, but I wasn't allowed to write, draw, or really do anything with my left hand while at school, even during breaks. Nowadays as a result I can only do things with my right hand even though I still, every single time, naturally go for my left.
I constantly go to write or draw and go "why is this so hard?" only to realize I instinctively used my left hand instead of my right.