Quick decision making is a quality good leaders possess. It comes from years of experience and confidence. For these leaders, when they are clear about something and their decision has no earth shattering consequences, they decide right away. This saves time and keep things moving.
Other decisions which they are doubtful about especially those with higher consequences they wait it out and think about it. Sleeping over somethings make things clearer.
Their mantra is when in doubt, wait it out!