umm, no amount of being careful will stop a person from hitting you and running.

Yes, stay aware, but putting fear and doubt into your mind will make you a danger to yourself. Do the right things with confidence and authority.

I say that cuz we were riding today on long downhill section, I was following my buddy who was going "slow"... 30-32mph, which was also the speed limit. Normally, I'd take the whole lane. Well, I was following behind my friend on the side of the road (he doesn't like taking the lane) and not thinking about the situation...

Some a-hole decided that he was going to pass us going into a blind curve and his mirror nearly hit my handlebars. Had I taken the lane as normal, he'd have had to hit me on purpose to pass... most people won't do that. But LOTS of people will pass you close if given the opportunity and will run you off the road by "accident".

Don't be afraid out there or you'll put yourself into a more dangerous situation. Not saying that the OP's friend was afraid, but some people reading this thread might become too cautious and that can be very bad.