One mistake is working with people who say things like "don't make the same mistake twice." This type of fear-based motivation is counter-productive for both the employee and the employer. The new employee's self-confidence is already shot if they make a mistake. "You better not mess up again!" further undermines their self-confidence and starts a downward spiral. The employee feels progressively worse, their lack of confidence increases the probability of mistakes on the job and the employer's investment in the new hire is largely flushed down the drain.