I find a good long blast on the horn gets them shifting pretty quick smart.
The best piece of advice I was given about driving was from my dad when he told me to treat everyone else on the road like they are complete and utter idiots who could, and probably will, do something completely unpredictable at any time. It turns out to be pretty true in the most part and is a piece of advice that has served me well wether I’m on my bike, in my car or as a pedestrian.
No point in getting wound up, life is too short.