when someone does something unexpected, my first reaction is typically "what does he know that I don't?" rather than "what is that idiot doing?". From talking to other drivers, this part of my driving seem abnormal.

For me that depends on what this "unexpected" is. For example, if I see a car in the next lane and ahead of me start to slightly drift into my lane, my reaction is that I know what this idiot is doing -- he is about to switch lanes and he doesn't see me. On the other hand, if a car far ahead hits the brakes and I don't know why -- there my reaction is "he knows something I don't"...