Player Currency
Players play for something. There is an emotional reaction they are pursuing. Some players want to play with the cool toys and interactions of a game. Some want to play with the high-wire moments of excitement as they take a gamble and go for it. Some want to hear a story, some want to tell a story. Some players love that moment where they push a button and things all go wrong.
This is the concept of player currency – a way that a game can generate a way to buy player attention, a way to invest them. Many games can generate different varieties of currency all at once. Look into this, look at why people play, and listen to the things people use to describe the experiences they enjoy.
Everyone plays for a reason.