I got jokes about missionaries a lot when I lived in CA. I’d shake them off.
But the real story behind a Mormon missionary is that they pay their own way, they spend 2 years (18 months for girls) of their life serving God and their community. They are unable to speak with their parents, they are able to write weekly emails/letters (depending on where they are at). And behind them is a whole family supporting and praying for them.
There is a mom who has sent her son to an unknown land with faith that God will take care of him.
In a way it’s tithing. We got them for 18 years, and God gets them for two.
Think of this mom next time you see one of those boys (or girls) knock on your door. They are very important people.