Every time I'm driving on the interstate for long periods of time (or hell, even short periods of time), and I see large trucks with unusual cargo (huge tree trunks, pipes, weird metal machines that I can't figure out, roller coaster seats [seriously, yes, I've seen roller coaster seats on the back of 18-wheelers], etc), I imagine that unusual cargo breaking loose and bouncing all over the road, probably killing me.
The worst are those damn car-carrying semis. And I will go damn fast get around them.
I probably have a problem.
I also have irrational fears, when driving, about motorcycles (um, if they fuck up and manage to make me hit them, they will die, and that will completely be on my head for the rest of my life.