With help from StrangeCosmos:
1) A day without sunshine is like night.
2) He who dies with the most toys, is, nonetheless, still dead.
3) The cost of living hasn’t affected its popularity.
4) What was the greatest thing before sliced bread?
5) Of all the things I’ve lost, I miss my mind the most.
6) Diplomacy is the art of saying “nice doggy” until you can find a rock.