Fourth: economics. Since every game is reliant on this addictive incentive system, every gamer harbors a game theorist, a situational logician blindly valorizing the optimization of quantified indices of “growth” — in other words, an economist. Resource management is to video games what African-American English is to rap music or what the visible sex act is to pornography — the element without which all else is unimaginable. In games as in the market, numbers come first. They have to go up. Our job is to keep up with them, and all else can wait or go to hell.
Numbers and economic incentive systems show up in many games, but they're not fundamental. Take a look at games like Journey, Portal, Gone Home, Yume Nikki, or many others which work just fine without numbers. The creator of Undertale, Toby Fox, had this to say in an interview (http://existentialgamer.com/interview-toby-fox-undertale):
TEG: I really loved the fact that many of the branches in UNDERTALE‘s story seemed to lead to miniature “voids” where I was forced to contemplate what I’d just experienced without being “improved” in any quantitative way. Do you think that as gamers and people we have become addicted to numbers / money / experience in general?
TF: The addictive quality of “numbers increasing” is what drives a lot of games. But some of the most important things in life can’t be accurately represented by numbers. As for people’s lives, I have no comment.