From Introduction: "It is quite simple: When you play a game, you want to win. Winning makes you happy, losing makes you unhappy. If this seems self-evident, there is nonetheless a contradictory viewpoint, according to which games should be “neither too easy nor too hard”, implying that players also want not to win, at least part of the time. This is a contradiction I will try resolve in what follows. The question is: Question 1: What is the role of failure in video games? Question 2: Do players prefer games where they do not feel responsible for failing?"
Also discusses the notion of flow introduced by Mihaly Csikszentmihalyi, according to which the challenge of a given activity forms a narrow channel in which the player is in the attractive flow state, at a safe distance from either boredom or anxiety.