when driving to work I've experimented with differing driving styles. The one that gets the best on road results, and leaves me feeling my happiest, is the ultra polite. Look to help another road user at every opportunity and never being pushy or agressive. I find a smile/wave/nod can be a pick-me-up in both directions.
I wonder if some of the behaviour of car drivers is enabled by their disconnection from all around. An acknowledgement from a pedestrian or cyclist could well serve to curtail this estrangement. Certainly I read plenty of cycling advice that highlights the importance of making eye contact whenever possible. Maybe drivers would appreciate that contact being friendly or appreciative, sometimes, rather than warning or judgemental.