I guess I'm lucky in that I'm broad shouldred and stand six foot two in my sealskinz, this is usually encouragement enough for angry drivers to stay in their vehicles.
The real truth is that I am, in fact, a tea slurping wuss who once gave a harmless two fingers to a driver who then chased me for one and a half hours.
Although I got away unharmed, the shock of the incident put me off my bike for five whole years.
I find now that if I show exasperation rather than anger I get to let off steam but I'm not necessarily 'challenging' the offending motorist.
It is hard to keep your temper in check but it pays dividends.
Stay safe you lovely lot.