In the kids' judo class my dad taught, the sweet and unassuming students who could and would wipe the floor with you in a few seconds were mostly girls. Dad laughs about the sudden "oh shit" realisation of various boys (and occasionally grown men) who he put them up against to train.
Alasdair StuartThere's a Bernthal quote about how the guys yelling about how badass they are never the people in a martial arts class you have to worry about. it's always the quiet ones. I used to train in the same class as a US Marine. Dude was funny, chatty, great teacher. Actual trained killer. Sweetest guy.