My tastes of games changed when I started gamemastering GURPS instead of D&D. Without dragging the mechanics of those specific games into the argument, I’ll just say that I grew dissatisfied with D&D because the universe consisted of a known palette of approved monsters, each with known strengths and weaknesses, who were nearly always of a fixed alignment, with known treasure types.
At that time, I liked games of the predictable, almost autistically mechanical style, which mirrored the tactical certainties of D&D: if you have fire, then you can defeat trolls. If you fight zombies, don’t cast sleep. Certain strategies always worked in certain situations against certain enemies. Similarly, if you have the newspaper and the matches, then you can fly the balloon; if you have the lamp, you can go through the dark room.
GURPS could be filled with people — people with flaws, with weaknesses, with great strength of character, each of whom was different, with different motivations and equipment. The RPGs I ran for my players became less about how to get the Magic Trinket to defeat Enemy X, but how to gather allies against him; how to discove what Enemy X wants and why; how to interpret something mysterious that your friends or foes did. If you want Ally Y on your side, you must do A, B or C, but A is horrific, B is impossible, and C is conciliatory. What do you choose to do?
I began to prefer games like Baldur’s Gate over games like Diablo, where the game is as much about tactics as about political harmony within your team. It makes it more real, and more tense, to know that Edwin and Minsc will come to blows eventually if you try to put them together, or to know that sometimes there isn’t a happy ending where all of your followers get what they want.
I prefer people-puzzles to trinket-puzzles, I guess, because there’s more narrative strength in people. The newspaper doesn’t care if it gets burned or not.