Discipline - The Theory - Take 1

I have been meaning to write about discipline.
I even started a blogpost, but then had so much more to add and wanted to make it "whole", "round", "cohesive". This was 5 days ago and I haven´t had the time to continue.
What is discipline really about, I ask myself.
Of course, simplified, it is to keep at something you decide to keep at.
But that seems such a banal and one dimensional definition.
I think already the concept of discipline is irritating me and I am wondering why.
More to come on my thought about discipline, but what I know today is this:
It´s much easier to just have my "verbal diarrea" of whatever comes to my mind, then to sit, regularly, and work on what needs to be worked on.
I need to think about this.