Martial arts develop beneficial psychological changes in practitioners and encourage good moral and ethical development
If you ever expect to face and defeat pure evil, you must train as hard as the predators have training and try as best you can, as a "normal" person, to prepare yourself mentally for the moment. You may train in Taekwondo for many years and enjoy every minute of it, but unless you are willing to train for survival, do not ever think you will stand a chance against a human beast.
When you are afraid, you do not always do the things you want to do. Fear causes undue stress in your life and your family. Fear is passed on to children so they learn to grow up in fear. Taekwondo helps you alleviate and control many of your fears.
There is violence in the world
There are bad people in the world who have no morals or conscious so they will not hesitate to harm or kill you. Some think that putting evil people behind bars for a lifetime is punishment enough because the wrongdoers have to think about what they have done for everyday for the rest of their lives. This is the wishful thinking of people with a conscious. Evil people do not dwell on their crimes because they do not have a conscious. They may not enjoy prison, but they do not regret their actions. If released, they will do the same things again. You must learn to defend yourself against these bad people.