We must admit that everybody will commit mistakes. If the mistakes are big, hurting other people, we shall be punished by law. Therefore, we should always keep ourselves alert, not to create mistakes which will bring us troubles even disasters afterwards.
But, we are human and we may commit mistakes unknowingly. Some fatal mistakes will bring ourselves to the hell, no chance to remedy even we want to.
Every human has different mistakes and it is difficult to set examples in writing. But, one thing can be sure that if we have wisdom, we will have less chance to commit mistakes.
In prison, there are many prisoners, most of whom committed serious mistakes which were impossible to remedy. They had to be in jail to compensate the mistake.
From the plays of Shakespeare, we see all the persons committed so serious mistakes that they could not remedy. They had to pay their lives for what they had done.
We are ordinary people, and we must not commit serious mistakes which will be sure to bring us troubles and even disaster afterwards. Life is a long journey upon which we have to travel with a great care in our life time.