The general who wins the battle makes many calculations in his temple before the battle is fought. The general... — Sun Tzu

The general who wins the battle makes many calculations in his temple before the battle is fought. The general who loses makes but few calculations beforehand.

Author: Sun Tzu

Insight: Most of us live like the losing general. We wait until the problem arrives—the argument starts, the deadline looms, the health crisis hits—before we seriously think about what to do. Then we scramble, improvise, and wonder why we feel constantly behind. The winning general, by contrast, does the unglamorous work first: imagining obstacles, testing assumptions, planning responses. He's already fought the battle dozens of times in his mind. The surprising part is that this kind of thinking doesn't require being naturally strategic or brilliant. It just requires sitting still long enough to ask hard questions before you need the answers. What could go wrong with this decision? What am I assuming that might not be true? What will I wish I'd done differently? These aren't complicated thoughts, but they're the ones we skip when we're tired or eager to move forward. The difference between winning and losing often isn't intelligence or talent—it's whether you did the calculation work when you had time. The general with few calculations beforehand isn't lazy or stupid; he's just started the real battle before he understood it. By then, his options are limited and expensive. You can choose differently. The temple—your quiet thinking space—is always available before things get desperate.

Source: The Art of War, ch. 4