And it's just good business to demand quality . But if it's an employee, no. You definitely want to discourage laziness and carelessness, but you also want to encourage experimentation and risk taking. In that case, there's nothing wrong with honest mistakes, unless you keep making the same mistakes over and over again. You can make the most of mistakes by learning what not to do again.
Scientists look at mistakes as steps .
The most valuable part of the process of elimination. Identifying the dead ends. But don't forget to look for the unexpected wonders mistakes are famous for. I don't think I need to list for you all the great inventions which were nothing more than honest mistakes that somebody noticed. The most creative people in your organization will be the ones who make the most mistakes.