Why is it so difficult to accept mistakes?

It is the conditioning of the brain during our growing up years which make it tough for us to accept mistakes.  The constant corrections, immediate reactions of people around us, being shamed for the wrong done, giving examples of role models who never erred and many other incidences happen during growing years. These instill a fear of making mistakes and getting caught. Out of all the emotions, guilt and shame are the toughest ones to be owned. So there is a hesitance to make mistakes and to accept it.

I think Ego is one thing which hurts. No one want to see their mistakes. I really think you should keep on trying, even if you think that you are committing mistake. Mistakes teaches you a lot.

I guess our ego gets in the way.

it depends on human behaviour for some it may be due to ego and some it is due to fear.for some that he don't want to be bad before others

It is very hard to accept the mistake,finding the others mistakes is very easy whereas the mistake is done by you,your ego never accept .

Because everyone tries to show himself as a perfectionist, now one will show his mistakes. Everyone try to show that he will never do mistakes, That's why no one accept mistakes.

It is not true that people do not accept their mistakes. They accept their mistakes themselves and learn from it, but the only thing is that they do not convince others about it. It is a symptom of narrow mindedness and happens due to fear of losing their individuality. 

I agree not all people are open to accepting mistakes. However, I am open to feedback both good and bad. Learning from mistakes (if pointed out in the right way) can help us learn and grow.

Only for false ego some peoples don't like to accept mistake. If we want to improve we must be accept our mistake. If we do not accept our mistake how we can correct it.

Some people cannot accept their mistakes because of their ego. All people are essentially ego-driven creatures. In some people, the level of ego is very high. Such people are not ready to accept their mistakes. They always think that they are always right. People with high level of ego can never succeed in life because they always follow the wrong and never accept what is right. Mistake is a way to learn. But people with ego fail to learn from their mistakes. Their life is a failure. Always remember that ego is a virtue rather than a poison.