I have seen many of the people that I taught to trade either give up or lose their initial investments when they trade. I do agree that it is not just discipline that is needed but also a lot of patience and proper knowledge of the coins that you are investing with. Sometimes my colleagues and friends tend to watch too much stock market videos but all you need is a sound mental faculty so as to avoid feeling too excited or too panicky.
You are right. mental abilities that are sometimes difficult to achieve. people can read and see theories about trading. but when it comes to trading itself the situation will be different. I experience it myself and try to improve it in every trade I make. to be honest it's not very easy.