Ho Do You Become?

How do you become on of those people that smile all the time. And I'm not talking about beautiful women with perfect teeth and great clothes. I'm talking about the old ladies that can't see well, can't hear well and walk with a walker around the grocery store, yet they still smile everytime you say "excuse me" to walk past. It must take something directly from the good Lord, because I see plenty of young girls that scowl and complain and less of the old people that do.

How do you become on of those people that don't complain. I know my husband would like me to figure it out, but seriously. How do you just take the bad for years and years, and not say anything? How do you just swallow when you took a really big bite?