There is a huge misconception when it comes to self discipline, there is this idea that you have to be very controlling about what you do. For example a person that want's to follow any specific diet stays hone and he concentrate very hard to don't eat cookies.
Self discipline is actually the opposite of that, the purpose of it is to cause changes in your mind and body to the point that you are a changed person.
By putting pressure on yourself you transform who you are, being self-disciplined about your diet doesn't mean to use willpower around cookies, because willpower is a finite resource and you will eventually fail and eat the cookies, when you are self discipline you reach a point where for the majority of the time you don't fell like eating the cookies, so staying on your diet is rather effortless.
Diamonds are made under pressure if you are going to put pressure on you by making yourself to do things that you are not very good at, there is a very high probability for you to fail. My definition for self discipline is the willingness of an individual to fail under pressure.
It is the opposite of self control, because by practicing self control you are trying to never fail, you are going to start this new diet and never relapse. Which is almost impossible.
When I say failure, I don't mean failure like the type of it, when people give up where they know they have problems, they just don't do anything about it so they just accumulate all this negative momentum in their life. That is not self discipline because there is no pressure in there, no desire to grow and change.
Not only your willingness to fail is important but also the variety of failure you try, as doing the same thing over and over again and expecting different results is insanity. You get new ideas of trying new things either by watching other people that are good at what you do or by understanding what you are attempting to master better.
Unfortunately the world is not very friendly with failure, there are very little people out there that normalize failure. Also you were educated to resist failure in school, whenever you made a mistake your teacher punished you to "help" you learn. This makes normalizing failure a little harder because you have to overcome the indoctrination you received in school.
