Are employees ok to make mistake?

No one is perfect in this world. Everyone made mistake before.
When we are small, whenever we made a mistake at home, our parents or guardian scolded us. After that, they still forgive us. We are still given a chance to correct.
When we are a little bigger, whenever we made a mistake in school, the teachers will lecture us and will still forgive us. We are still given a chance to improve.
When we are an adult, start working in a company, if we make a mistake no matter it is big or small, we are immediately get warning, screwing, and even firing. The worse is no matter how you have contributed to the company, even you help the company to earn/save millions of dollar, you will still be black marked, and will not be forgive or forgotten by the employer. In a company, employer take contributions and hard work of subordinate as a must but mistake is always not tolerable. Is this fair? The society is not encouraging people to make mistake but who don't make mistake? The only problem is they just don't give chance for you to correct and improve.
Worst case scenario after making mistake is you get panellize and jail term. Once you reach that phase, the world will not forgive you... Come on la, we are just human, try to give people a chance to show that they have changed to better! Else, those people will most likely end up behind the bar again.