There are several established games:
1) The Big Game
2) The Little Game
3) The Fun Game
You can also make up your own game.
If you don't decide what game you're playing, it's tough, because you're less sure how to win. You have to think more about every decision. You're easily influenced by others who may or may not be playing your game.
You can, of course, decide to change games. But you should be conscious of that.