Sometimes, you may be the one to discover a mistake you've made at work. If no one else has mentioned it, it can be a struggle to decide to bring it up. However, says Gunsalus, the best course is to speak up immediately. "One of the first rules of being in a hole is to stop digging," writes Gunsalus. "When you make a mistake, trying to avoid embarrassment by covering it up can get you in serious trouble."