Don't Procedure To Death
I hate making mistakes. Mistakes made from a lack of skill or knowledge is one thing, but to drop the ball on a task you regularly perform is especially frustrating.
The knee jerk reaction is to put policy and procedures in place making sure it never happens again. Sometimes that's the best course of action, as costly mistakes should not be repeated. But there need not be a procedure for every mistake committed.
Sometimes an honest mistake is just that, one where busyness or distraction gets the best of you. Don't create a complicated system of checks and balances for every menial task. Keeping a standard of quality is important, but so is not bogging down the organizational machine with endless procedures.