Mistake

I have to remember every mistake, even a minor one, for the tiniest defect may cause a catastrophe sometimes.

Must learn to be careful, and then learn to be more careful.

To be honest, I made a mistake today, so I must learn from Yen-Hay:
Never make a second mistake like the first one! By the way, thanks those people who find fault with me (I am saying this in a positive way).