You'll Learn Sense...

What do you think that means?

It means that you will learn that it is best to heed the advice given to you instead of having to go through what you were advised against doing.

Does your grandmother, grandfather, or another family member have some saying that they always say?

Yes. "Laughing is catching."

What do you think those saying mean?

I am not quite sure, but I think it means that if you laugh at one person, sooner or later, someone will laugh at you.