It means the best way to live is to take pleasure in what you actually have, rather than being disatisfied and wanting things you can't/don't have. It's not worth describing a whole context for when it would be appropriate to say this. We'll just suppose you know somebody for whom that sentiment would be good advice. Say it then, and everything will be fine. Unless he doesn't understand you, in which case tell him to watch [the 1938 movie][1] [1]: http://en.wikipedia.org/wiki/Gold_Is_Where_You_Find_It