Discipline for whom and towards what ends?
It seems the only worthwhile form of discipline is self-discipline. This is the type of discipline which is only internally-regulated. Which means:
You posit your own personal goals, ends, and means in life … and the only reason you pursue ‘self-discipline’ is in order to achieve YOUR own personal end goals and desires/needs/wants.
For example, I am insanely vain about my self and body. Thus for me, the self discipline to NOT consume sugar and other random crap is not ‘hard’ … this discipline is motivated by my own personal vanity, which makes it very easy to say no to any foods or drink-substances that don’t accord with me.
In terms of protecting my own focus; I prize my own mental clarity and focus above all. Thus to NOT do anything which disturbs me… this is very easy for me to do.