Forms, even at this point after having practiced martial arts for the first time 15 years ago, I still love forms, I even arranged with my sifu a special 1 hour class only on forms, and well, martial applications, but mostly the form sequence itself, how each move works, where the force directs to, where your weight is, all the different meanings for each move, all the different ways to do a whole sequence, the topic is so vast and mysterious, and when my sifu demystifies each move I'm wowed, all the time. I leave that class and my face is like a big WOW lol
Second thing was, splits
After watching Van Damme do it on the ring ropes in that first movie he was not even the main character, No Retreat No Surrender. I think I must have read and practiced 99% of the stuff on flexibility out there. Thomas Kurz, Pavel Tsatsouline, Bob Coole, Kit Laughlin, Michael Alter, GMB, Paul Zaichik, just to name a few and the most important ones.
So I love forms, splits, high kicks, and funnily enough not the actual reason for a martial art I think, which is killing...