Tae Kwon Do has a common root with Zen in that they both come from the idea of meditation. The amount of discipline needed to be successful in Tae Kwon Do is enormous, but you will also develop that discipline as you train. By doing forms (a Tae Kwon Do exercise of moving meditation), a Tae Kwon Do student is able to focus all of their mind and power in the direction of a single goal.
Tae Kwon Do is all about living like a warrior. Before you jump to conclusions, you need to realize what a warrior is. A warrior may be very skilled in fighting and battle, but he/she is mostly defined as one that is a master of self-discipline. Therefore, it is through the discipline that one trains to achieve that they are able to see success in battle.
If you are starting your martial arts career and want to join a Tae Kwon Do school, you should make sure you are fully ready and armed for the training. Aside from the physical skills and equipment, you must focus your mind to be ready for the task. Yes, Tae Kwon Do is a training system that can lead to an expanded knowledge of self-protection, but that is more of a side effect than anything else. Through meditation, practice, and a disciplined approach, a Tae Kwon Do student can reap benefits that they never imagined were possible, just by exercising and training in the martial arts.