What makes an overly urgent and busy life so dangerous?

I was recently flipping through Greg McKeown’s book, Essentialism, and came across this quote that I had highlighted:

“If you believe being overly busy and overextended is evidence of productivity, then you probably believe that creating space to explore, think, and reflect should be kept to a minimum.”

It is dangerous to be overly urgent and busy. Because it will distract us from slowing down.

What makes an overly urgent and busy life so dangerous?