What typically happens when you waste time doing something negative:
(as borrowed from my seventh grade teacher, Maurice Ehinger)

• You have lost the time and money spent on the negative endeavor.
• You also sacrificed doing something productive.
• You lost the profit from the good thing you could have done as well as the investment to do it.
• You may have damaged yourself and your reputation while not learning how to do the good thing.
• You have lost time with friends that can't be made up.
• You may have lost the experience needed to do the good thing better next time
• You now can't easily reverse course, you sacrificed your queue position, your contacts, your needed education, and your resources.
• You have tainted your outlook so that all you can see now is the negative thing. There may not even be a simple "good path" anymore!
• The rest of the world has moved on and their priorities have changed!
• Moping around, thinking about the all those ice cream cones you could have eaten is, recursively, the same type of waste. So don't forget to mope about the moping about the moping!!
• Not doing your homework, taking seventh grade English a second time is: .........
• Being indecisive is also:....
• Writing such silly web stuff can assuredly be:......

It was upon such a note that Mr. Ehinger would wax melancholy and the lecture would suddenly meander off toward some topic like intransitive verbs or the Gettysburg Address!! However, maybe he knew something because over 2/3 of the students in that inner city class became doctors or lawyers or PhD's despite the crime, poverty, and invasive pandemic despair.

"Waste not want not" is one way of saying it but I like a quote I found in Bob Parsons sixteen rules (founder of Godaddy and Parsons Technology, the original Turbotax people) from General George S. Patton, he said: "A good plan violently executed today is far and away better than a perfect plan tomorrow."