Flip the bird? Nope. Pull in front of them and slam on the breaks? Regrettably not. Tail them until they reach their destination and chase them with a shirt and no pants on? Only once…otherwise no.
How I deal with bad drivers is I pull alongside of them, shake my head in disappointment, and then continue on my way. As if to say, “It’s really unfortunate you that suck at driving so much.”
Their response to this can either be to do better, or passive aggressively make my journey harder by tailing me or not letting me merge or something of that nature. Regrettably the latter is the most typical response. In which case………I shake my head.