Confusing motivation and discipline

I'm seeing more talks about discipline > motivation. I think the two can often be confused with, especially when one has limited self-awareness.

To keep it simple, I believe discipline is long term, standing the test of time. We are talking decades. I understand and appreciate the importance of step by step, therefore it is valuable to look at things on a weekly, monthly and yearly basis first. But let's practice being mindful about what truly is motivating us and what is discipline.

I find this distinction important as many people, including myself mistake motivation as discipline. Discipline is often doing something even though the IMMEDIATE response seems to be not to do it. Doing it for the long term reason, an investment. Working with some young males, they say their motivation to go to the gym is "to impress girls". They also speak about the importance of "the grind", "the discipline" etc: words they use interchangeably. I think the distinction is important as once this said goal is achieved, they are often left with a deterioration of motivation. Why did I start in the first place? Although in their defence, they have started a good act/routine through potentially misguided motives.