No matter how good your words seem in that last draft of the evening, there’s always room for improvement in the cold light of day.
I learned many of my writing skills in an era when “cut and paste” required scissors and Scotch tape. Now, I make my edits with a pencil (and eraser) then transfer them to the computer.
I actually thought this draft was pretty good, but as soon as I looked at it I saw things that I could improve. That’s the way it works most times. You know you’re done when you can’t think of anything else to say better.