Life is a game.
Of course life is many things, but what we are saying here is that life is best understood as a game, or more precisely, those who model life in terms of GameTheory tend to do better at life. That is because they think in terms of competition and co-operation, they use DecisionTheory to analyze possible moves and outcomes, they model other players and their respective strategies, and they are cognizant of how sub-goals relate to their super-goals.
See other InterestingMemes.