I have only ever beeped someone twice, once as I was on a single lane roundabout (already part way round) and someone pulled out right in front of me- not just a misjudgment as he certainly couldn't have looked as I was right there. I had to emergency stop and luckily nothing was right behind me, i beeped and was tempted to follow him not to unleash some rage; but to make sure he understands how dangerous it is not to look before you go! Someone with slightly slower reactions (not claiming to be a ninja btw) would have gone right into the side of him. The second was someone who did an extremely dangerous overtake and my reaction was to beep. I have only been beeped once and it was my fault so when we got to traffic lights the car was behind me and I put my hand up to acknowledge i was in the wrong. Every time i drive though there is a temptation to beep some maniac but on the whole i just let it go.