I used to get really stressed when driving and shout + scream at everyone about their bad driving without first considering my own actions and mistakes.
( Read I still do inside but the constant wifey will beat me with a ****ty stick thought has trained me well )
Yes the roads are a hell of a lot busier nowadays but they are also full of people moaning groaning and bullying their way around the place in mobile weapons of mass destruction. ( BMW = Bloody Moody ****er )
My advice is ignore the idiots - don't rise to the bait - be patient - KEEP YOUR DISTANCE.
I agree with andy about Milton Keynes ( crossing a roundabout at rush hour is like being in a 1970's motorcycle display team doing the crossover in the middle of the summer fete display arena ) get your timing wrong and your screwed. In fact ( much like a lot of the UK ) it has got so bad that many of the major roundabout junctions have traffic lights around the roundabout to reduce the number of serious accidents during peak hours..
My pet hate - tailgaters + foreign truck drivers.