I've found that letting off the gas ever so slightly will remedy most of them. If they don't back off after that, I brake check them.
I really enjoyed driving in Texas. A lot of their roads had really large shoulders, and I regularly found that Texans would actually pull over ONTO those shoulders to let faster moving cars pass. I felt like I was in heaven.
Unlike Florida, where people would make left turns from the far right lane, among other things.