No matter what. I think it is the motto. It’s not about behaving silly in situations that require being serious. It means “think positively”: Problems are just challenges, challenges make life interesting. Challenges make you better. If there are none, just have a look around: life is just damn beautiful! It is not easy, to keep this attitude. Especially in a group of people, be it a couple, a group of friends or the whole office: everyone should contribute. But think of it: how awesome it would be, to always see a smile, determination to continue, to challenge, to get shit done.
Stay positive. No matter what. And things could just get a little more pleasant.