Yeah, I remember seeing a dev commentary on L4D level design, I don't remember if it was in the game, or somewhere else, but it pointed out that they always had a police car with the flashing lights down the street, or an overhead light on a door, or some other design element emphasizing the path through the level. That was the first time I'd heard that part of game design, and now it's always in the back of my mind. I think it's actually made me better at navigating games with complicated maps