I don’t remember the exact quote, but I was reading one of Rory Miller’s books and came upon the observation that martial arts is about taking healthy bodies as your raw material and turning them into cripples or corpses. That is true.
Most martial artists train for reasons beyond cultivating the ability to hurt people. Some do it for sport, others for emotional control, others for fitness, others for connection with the family and friends they train with. There are a lot of reasons why people train martial arts beyond hurting people. Nearly all of us who came for self-defense have stayed for a number of those other reasons.
Nonetheless, the irreducible basis for our terrible craft is doing damage to the human body. If you just like to play rough, you could be doing hockey, rugby, or football, where the object of the game is something other than hurting the other players. (Unless you play for the New Orleans Saints.) If you just like movement and tricks, you could be doing acrobatics or freerunning. If you’re in it for the magic of contact and camraderie, you could be doing ballroom dance, partner yoga or Contact Improv.
But you’re not. You’re doing punches rather than planches or plies, and there’s a reason for that. It will be worth your while to inquire into what that reason might be. The answer I get most often is, “I have to stay active, and this is way more fun than running on a treadmill.” Don’t stop there. Not everybody thinks dodging punches is more fun than a treadmill–why do you?