I make also my screw-ups. But I make a division between normal screw-ups and stupid screw-ups. A normal screw-up could be cutting on the wrong side of the line, something exactly 100 mm too short, holes too deep or too wide.
A typical stupid screw-up was when I made a drawer cabinet for small tools and hardware. I make this sort of cabinets to a fixed form, a frame, plywood sides, plywood drawers and wooden rails. To make a cutting list I had set-up a spreadsheet for earlier cabinets. I type in the width, height, depth and the height of each drawer. A large cutting list of all components will be produced with a simple press on the Enter-button.
The width and depth should be 500 and 600 mm. For some reason I typed in 400 and 500. I started cutting in assembly line style. In record time I had a stack of plywood panels and frame parts. When I started assembling, I was a little disappointed about the storing space it had. Only when I put it in place, I saw my mistake. I will spare you the next 30 minutes after installing.
After a week I started all over again and could use the wrong cabinet somewhere else.