For real world games I want realism. Sci fi is perfectly ok with me as long as there is some internal logic.
For some reason I don't mind the levels in DnD maybe because it is totally fantasy. I always liked playing spell casters as I felt choosing spells was like a chess game. Even when I played other types of characters I was never really into hack and slash. I preferred battle management like using spells to move the enemy in a certain direction so they would be easier to kill.
A was a little bit munchkin in counting treasure though. I would always go out of my way to take everything that was not nailed down. (Within encumbrance limits of course). But in the end My wizard had a tower pretty much furnished with "acquired" goods. Maybe not a munchkin but more of a miser
Also when I was DMing a dungeon had an internal logic as well (unless the builder was insane). Creatures always had a place to go to the bathroom, a food source etc.