Being specific about what you want and how you will achieve it helps you say no to things that derail progress, distract your attention, and pull you… - James Clear

'You're probably right' has become one of my favorite phrases.

Whenever someone disagrees with you on a small matter (read: most things), you can shrug, say 'you're probably right' and move on.

Not caring about winning trivial arguments saves so much time and energy.

The normal behavior of the tribe often overpowers the desired behavior of the individual. Most days, we’d rather be wrong with the crowd than be right by ourselves.

A practical definition of opportunity cost:

If you spend too much time working on good things, then you don't have much time left to work on great things.

Understanding opportunity cost means eliminating good uses of time. And that's what makes it hard.