I can be sad that my car is old, I can be sad that I didn’t have a good relationship with my father, I can be sad that I don’t make as much money as I would like to make; or, I can be happy that I have a car at all (many people don’t), I can be happy that I had a father at all (many people never meet their fathers), I can be happy that I make any money at all and that I have a home to sleep in at night (many people are jobless and homeless).