Modern Pillars of Play
There are three elements that define the gameplay of a TTRPG, and that motivates Players to play.
They are: Solve, Be, and Weave.
SOLVE
Problems are put down and Players engage with the game in order to solve them. This problem can take many forms: a dungeon to explore; a stubborn NPC that needs to cooperate; a combat to overcome. Players that enjoy to play in order to Solve desire challenges.
BE
The game allows favors the Player to Be a character, to act in a way they find interesting or amusing. Situations in which there are no inherent problems to Solve are presented: a moment of respite on the campfire where the Players may talk, an interaction that serves no inherent story purpose or problem to solve. The purpose is simply to exist in that world, in that scene, in that moment.
WEAVE
The game allows favors the Players to make decisions to further enhance a story being told. The situation holds no intent to Solve, nor is it simply Being in that space, but upon an external knowledge of story beats and arcs and even dramatic moments, the Player finds enjoyment in interacting with the world in order to Weave this tale. Needs a knowledge external to the Character, or a meta point of reference in general from the Player.
EXAMPLES
Murderhobos - Be extremists. Don't want to solve anything, nor Weave. The world is a sandbox for existing in that world in a specific way.
Story games - High percentage of Weave. Moves and abilities allow for Weaving as much or even more than Solving.
Tactical games - High percentage Solving. Every environment creates problems to work out.
OSR games - Favors Solving. Principles reinforce the idea that character knowledge and player knowledge separation is not critical. Weaving is not as important as creative solutions, nor as favored as abilities that allow them.
Simulationist games - Favors Being. External influences over character decision are repeled.
Daggerheart (System) - Favors Weaving and Solving. Being is not as important as the tale and the challenges.
Mork Borg (System) - Favors Being and Weaving. Problems are pretext to act in interesting ways, telling an interesting tale on the end of days. Abilities favor flavor and evocative themes instead of strict Solve potential, which eases a Player into Being.
Mythic Bastionland (System) - Favors Solving and Being. Abilities favor evocative over strict usefulness or Solving capacity. Players are put into situations that external logic won't work plainly, favoring Being in the situation.