In a world that glorifies hustle, perfection, and 100% completion, it might feel counterintuitive—even uncomfortable—to purposely leave things unfinished. But according to Alec Mackenzie in his classic time management book The Time Trap, learning what not to do is one of the most valuable skills in business.

“I sometimes like to measure a man by the things he decides to leave undone. The man who insists on getting 100 percent of his job done either doesn’t have enough to do or doesn’t have the kind of stuff it takes to succeed in business today.” (The Time Trap)

This quote flips conventional wisdom on its head. Rather than praising those who complete everything, Mackenzie challenges us to consider that effectiveness comes from selective focus. In today’s fast-paced business environment, trying to do it all can actually signal a lack of prioritization.

Why Doing Less Can Lead to More Success

The idea here isn’t laziness—it’s strategy. High achievers often have more on their plate than they can realistically complete. The key is identifying what matters most, then giving those priorities the attention they deserve while letting go of the less impactful tasks.

This concept echoes the 80/20 principle: 80% of your results come from 20% of your efforts. Spending energy trying to perfect the other 80% of your to-do list may result in diminishing returns—or worse, burnout.

A Call to Prioritize Ruthlessly

Rather than striving to check every box, business professionals should be asking:

  • What tasks truly move the needle?

  • What can be postponed, delegated, or dropped altogether?

  • Am I trying to do everything, or am I focused on doing the right things?

Time is a limited resource, and not all tasks deserve equal treatment. Mackenzie’s insight encourages a mental shift from doing more to doing what matters most. The most successful people and companies aren’t necessarily the busiest—they’re the most focused.