I guess another reason I don't have much problem with it is I'm generally outpacing everyone around me, and I build a mental map as I go. So I know where people are behind me without looking to begin with, the mirror/look checks are just double-takes to make sure they didn't do something totally unpredictable. (Well, and the rear view checks spot oncoming faster drivers, but even though I scan it religiously that's pretty rare heh. Usually more likely to find the fuzz there
)