It sounds like good advice, and those who peddle it are usually well-intentioned. But like many feel-good ideas designed to ignite motivation, it does not hold up well under scrutiny.

What no one tells you is how laziness or discipline often have little to do with your ability to apply effort to your endeavours. What shows up again and again as the real limiter is clarity.

You might find yourself thinking “I’m tired.” or "I don't feel like doing anything." and respond not with “let me clear my mind” but with “I can’t be tired—I ate this morning and I have things to do.”

In theory, “I have things to do” should trigger action. In practice, it often does the opposite. It intensifies the feeling of “I’m tired” and “I don’t feel like doing anything.” Not because it’s a useless tactic—sometimes it works—but because its application is being served in situations where lack of clarity keeps its relevance out of attention.

When you don’t know what’s happening, when things feel vague and unnamed, it’s easy to push through without regard for clarity. But pushing through has its limits. Ignore the limits long enough and an intervention becomes inevitable. Your body, for example, can trigger enough-is-enough: a mental breakdown, a heart attack, a nervous system that forces everything to halt.

You want to listen before you’re forced to listen. And do so well.

If you do, well enough, you may discover that “I’m tired” and “I don’t feel like doing anything” aren’t signals to engineer a better execution plan. They may be signals of something far more basic. Something physical. Something ignored.

You never hear that something as "minor" as heartburn can be the thing that throws your entire nervous system into complete disarray, so you never bother to look. You just think, I'm tired or I'm anxious, and bear witness to the mind looping around tools ill-suited for the suitation like "How is it going?" "What is the plan?" "What is the next smallest step?", in a bid to manufacture discipline or motivation and bring movement for progress into effect. 

The real non-negotiable is rarely motivation; it's clarity.

It suspends analysis and forces a pause, so that you might observe and update knowing. Analysis matter, but only at the service of sufficient observation. 

So, pay attention. Protect clarity or the mandate to distill it. 

Those who espouse “You can achieve anything you set your mind to” aren't far off from what they mean, which is "Set your mind on something and apply yourself to it." What gets lost in translation is setting your mind is a continuous act of orientation. And orientation depends on clarity. 

More often than not the work is not always to motivate, plan, or optimise. Sometimes the work is simply to stop and respond to: "Tell me what is happening."