always make the same mistake

All humans make mistakes and we cannot judge a person by their mistakes but rather on how the rectify the mistakes. If I understand you correctly you say you continue to do the same mistakes. Analyze for a minute, is anyone else complaining my friend. If not then perhaps sit for a moment and write down the actual repeated mistake and think about how you have repeated. You will find that perhaps this may help you understand to longer continue the repetitiveness of the error. If no one is complaining than perhaps you are too hard on yourself. If others are complaining then it is time to think, after looking at the advantages and disadvantages that you wrote down as to how to avoid and correct from future repeat. Good luck to you friend.