In many games, due to the complexity and randomness of it, the winner is mostly determined by the one who makes the least mistakes. It's a battle to reduce the amount of errors in your game play. Similarly, unexpected things can happen in life so we are bound to make some mistakes. It is pretty hard to go against the Murphy's law so it's alright if you screw up from time to time.
But I don't we should care all that much about mistakes. Yes, you need to try to minimize them and learn from them but ultimately, our lives aren't about tracking the mistakes we made.
Your life shouldn't be a score card for mistakes you made but a list of achievements and accomplishments you have. Don't let mistakes drive the story of your life. It's about what you did not what you did wrong.