As I was driving in first person, I noticed that someting was feeling quite unnatural, and that was the fact that my head's position was nearly locked in place. This gave out the impression that I was a static camera instead of a human inside of a shaky car in a troubled road.
I hate to give out this example, but I think Battlefield 3 has got this thing right. Whenever the player went through a messed up environment, the camera would wobble quite a lot. I don't think if this were to be implemented, that it should be quite as noticing as in Battlefield 3.