Four Freedoms of Play.

"Freedom to explore is a huge part of all play. The second one that comes with exploration often is failure. When you think about a kid playing a game, you are failing all the time until you succeed. And in fact, child play in general is moving from one failure to another until you succeed. So a child building a sand castle, or building a block tower is regularly failing without any pain. They don't even stop to reflect on it. They just keep learning from those failures until they succeed. So failure has to be present in play. And of course in games, if we didn't feel free to fail we would never play games because the risk would be too great. If we couldn't stand the failure in a game, you would never play it. So freedom to fail is important. Bad games I think sometimes don't know how to deal with failure, don't know how to incorporate productive failure into the game. The third freedom is freedom of identity. …The last one is freedom of effort, which is to say that sometimes we need to play hard, sometimes we need to be relaxed".

"The enjoyment that you get from the game isn't from the things bubbling on the screen and telling you that you're wonderful, but in fact from having that sense that you had a challenging problem, you did fail, and that was OK because you learned something from that maybe once or twice or many times. And then you succeed. And the euphoria comes from that success after a hard earned win."