Why have I done nothing wrong? Old people just don't like me to find fault with me and argue with me. What should I do if I am about to collapse?

You are not alone in this situation, and there is nothing you can do. Some old people may be unreasonable sometimes. The solutions are: first, don't fight against the old people; Second, have the opportunity to actively listen to their criticism; Third, don't show impatience with them; Fourth, if you are wronged, don't take it seriously and turn around and forget it.