What jokes have you heard that are actually meaningful?

I remember when I was a child, all of us who sold sesame oil were carrying poles and knocking on the bangzi, and we traded sesame seeds for oil. There is also a saying that sesame seeds are exchanged for oil (old price). That day, an old oil seller came to my village to sell oil with a burden, and Aunt Lao Li took her son to change oil. Aunt Lao Li didn't pay attention to fart when pumping oil. I'm sorry to say, son, look at your fart so loud. Honestly, kid, I didn't put it there. You did it. The old man selling oil was embarrassed to laugh, but he couldn't hold back. what should he do ？ He stopped selling oil, picked up a car and left. Aunt Lao Li told her son that it was the child who farted and the mother who made jokes. Her son was clever, so he shouted, don't leave the oil seller. My mother didn't put it there, I did. The old man said I wouldn't sell anyone who put it there.