I'm constantly walking a line between what I see as something that might take the user out of the experience and something that is just necessary in a game. This kind of thing (see picture below) is exactly what I mean. Repeating textures. Everywhere. This is a screenshot from the new game Aliens: Colonial Marines. The guys who made this game are not amateurs.
See that shit? But the reality is that you just can't have a million different textures all over the place. At some point, the player's brain says, "close enough, I get it, it's a wall with some lights."
...I just wish my brain would say that.
Because it doesn't. It says, "Look at that crap. Clearly, the gamer will stop playing in disgust."