Pet peeve: Employees or contractors who don't tell you when they've screwed up, or think they might have. And even more so, the prior bosses and managers who made them fear admitting mistakes.
I have seen more time, money, and customer relationships wasted on errors that were covered up by employees or subordinates, which could have been very easily fixed prior to becoming a real problem, if disclosed. This is one area where I think women often make better employees, esp. in tech fields, as they seem much less reluctant to admit when they don't know something.
Asking someone to double-check one small area of your work, especially when you're unsure of a particular detail, is not negating your contribution in all other areas!
