what's a game?

I'm not sure what to make of this…

In the reading Juul identifies six features that games have:

1. Rules
2. Variable, quantifiable outcome
3. Value assigned to possible outcomes
4. Player effort
5. Player attached to outcome
6. Negotiable consequences

These are pretty straight forward and make sense when thinking about what a game is. Juul also explains a diagram that outlines and categorizes if something is a game, or a borderline game, or not a game, based on how many of the six features it has.

However, after reading all of this and looking at the diagram, I'm not sure I get all of it. It's helpful in being able to talk about games, but I my gut feeling is that no matter which way you define a "game" or try to categorize "games" from "almost games" from "not games", something is bound to be left out, or not fit perfectly into one category. To me, "game" seems like more a concept that's too fluid and too dependent on individual perception to give a finite definition. Still, it's the best definition I've ever read.