Thinking, after a certain point, makes deciding harder.

Trying to calculate all possibilities in order to pick the best one, is futile, in a real world we just cannot know every factor. Not to mention, most of us shift the goalpost in the middle of our calculations.

Implying, the correctness of decision rarely improves when we attempt calculating everything, the window of opportunity is often lost, and there's less energy left to carry out tasks after this decision. Not to mention, the person still feels 'maybe something else would've been better'.

TLDR, when you can, decide quickly.