Without it, you either subject yourself to risk, or work harder than necessary.
Let it be your way of life - just don’t abuse it. “It’s better to beg for forgiveness than to ask for permission.” - Unknown
Doesn't make you competent. Especially if you don't know you're doing it wrong, which is the most hallucinatory situation of all. Your incompetence will be seen by those who know better, and you will soon be surpassed. For the quants: Always think critically. For the creatives: None of this applies.
But it does equal greater confidence. Which can be dangerously misleading.
Because if you don't, and you're up against someone who did, your opponent will likely win.
By setting the deadline prior to the deadline. When needed, that wiggle room will be appreciated. Possibly even a life saver. But don’t make habit of using it - that’s just reckless.
That which is life.