Interestingly, despite reading so many other threads where people complain about dump trucks, dump trucks around here have been among the most patient and pass me very safely here on the local roads in the counties around me. On the Natchez Trace Parkway, the cars that like to show their annoyance at me and get real close are almost always from out of state. Three states in particular, one very far away.
But on the whole, the instances of bad motorist behavior that affects my safety is still a rare occurrence IMO. I tend to have more issues with other cyclists on the MUP that don't stay in their own lane on blind curves. Or, they pass walkers when I'm coming the other way. They can't seem to judge my oncoming speed very well.