Quite often, I see this:
Forget it, I’m stupid, this is all wrong.
or
Sorry, I broke it, it was a stupid and unnecessary mistake.
While some mistakes are actually unnecessary and completely avoidable, I do not mind stupid mistakes. They are the best form of mistake: you made a mistake, you quickly realized what was wrong, you acknowledged it (mostly to yourself!), and then you learned from it. And you moved on from it!
Compare this to making “not-stupid” mistakes: Maybe it took years to realize you were wrong. Or you had to spend the last 2 weeks debugging what specifically went wrong in that one edge-case. That’s the actually expensive stuff. Maybe you just realized how much work you have to throw away now? Imagine you had not made hundreds of stupid practice mistakes before: How would you have learned to forgive yourself for your mistakes? How would you have practiced to own your mistakes and learn from them?
Next time when you make a stupid mistake, just be grateful that it was really just a stupid mistake, and not a colossal, expensive screw-up. They’ll come eventually, and this was just a practice round.