Seeing as Taekwondo is a martial art, I'd like to write about the art aspect. As a writer, trumpet player, and mathematician (yes, mathematics is an art), I've trained in a few different arts. Martial arts isn't that much different, except it requires a bit more of the physical. Your instructor critiques you, and you may or may not fix it on the spot. Nevertheless, a good instructor will give you something to work on for next time you meet (in all the arts). You go home and practice, or produce if that may be the case, trying to fix an inherent flaw. At first, this is restrictive and difficult. You must do what is told of you to improve, and you must practice outside of the lessons! The way you gain freedom to express yourself is through mastery of the basics. It is a perfection of the basic tools that allows you to invent and think and be creative and eventually start expressing yourself truly. It never seems that way at the time because there is always some way that we can improve and always something to fix and work on. In fact, when this happens, practice becomes almost routine and dull.
Think of the first form you ever learned. We struggled to get even the steps right, let alone whatever else needed to happen. But once the steps were down, we could move on to the techniques that occured (kicks, blocks, punches). But that wasn't even enough. Now we need to do them properly, crisply. The stances need to be deeper or more precise. Even then, now things are too crisp and the steps are too rigid. Eventually, it becomes a dance, more fluid, but every move crisp. Each time the same form is slightly different, perhaps slightly better. We turn our feelings for the day around and express them in the form. The motions are set and the techniques well ingrained. But we aren't restricted anymore even though each stage of the learning was restrictive, right? And it happens to some extent for every form after that. It happens in everything we learn in Taekwondo, and the art is cultivated through perseverance of practice outside the Dojang. Whatever happens inside the Dojang is just a small portion. It's only icing on the cake that you spent your life baking. Okay, now the metaphors are getting bad, so I better stop. The point is that most of what you are as a martial artist is accomplished outside the Dojang. The Dojang just tells you the direction to head once you leave.