Trust and Game Design
I have spent an inordinate amount of time playing, refining and ultimately creating role playing systems. Twenty six years, now, starting with Wizardry 1 back in 1981.
RPGs tend to be tightly controlled, deterministic systems where, baring cheats like the infamous “Identify 9”, the player gets control during combat and the choices they make in the storyline. Even then, and particularly in the storyline, I decide what choices you have available to you. So, while those decisions might have meaning, the designer ultimately decides what meaning these things can potentially have. Everything in the game was thought of well before you got there. The bricks were put in place, monsters were invited into that room, and behind it all, I had a big fat Excel spreadsheet or twelve detailing every permutation within the game.
Contrast this level of design with something like The Sims or Sim City or other sandbox-type games. Designers of these games will usually say (and have said in the case of Will Wright) that these games aren’t games at all, but toys. The level of trust that these designers have in their players is amazing, and I’m not the first RPG designer to face what I’ll call the “trust wall” in game design: if I give them the tools to do stuff and build stuff, will they actually do it?
The obvious answer to this question is literally within arms reach of me – yes. I have a bucket of Legos sitting there (an obsession with Legos is a warning sign your kid may be a designer, btw). Legos trust that I will just start putting them together. I’ll use them to build all kinds of crap. I don’t need directions or pictures or anything.
If you’ve played with Legos as a kid, you know what happens – the magic takes place in your mind as you build walls and rooms and doors and houses. I used to build castles and moats and little fake knights.
Designers can face the “trust wall” even with all this knowledge. The desire to put in a quest is overwhelming – “just so the player will know what to do.” And you know what happens from there. Quests turn into missions which turn into whole campaigns. Within 6 months or so, you end up with simulation game that has a structure stuck on to it by force, sort of like Legos that let you build whatever you want, but only reward you and encourage play when you build what the designer wanted you to build.
Applied Game Design 
It’s really funny that you say that, since legos are also a gateway drug into Programming. Think about it — most piece dimensions are a power of 2, and there’s all kinds of binary logic going on.
Strangely, I didn’t build “things” (houses, castles, whatever) with my legos, I built games. My obsession with Marble Madness drove me to make a turn-based marble-flicking game. I made go-around-the-track boardgames. I made a maze where the object was to get a piece through it by tilting the board, but certain parts of the maze were hidden so you had to go by feel.
I was a strange child, no doubt.