People beeping their horns at their friends

As well as being against the highway code, it's also fucking annoying. It's happened to all of us- you're driving in your car or often walking on the pavement, when some twat beeps his horn (usually the 'cheeky' two pips) at his mate he's just spotted on the pavement. So as a pedestrian, you shit yourself that they're beeping at you, and as a driver you think they genuinely might be beeping to alert danger.

So now, said twat has commanded the attention of pedestrians and motor-users alike as he tries to wave to his mate. At this point let me remind everyone that the receiver of this friendly beep horn never knows what the fuck is going on. They don't know if they were the one being beeped it, and they certainly have no fucking clue who's in the car anyway.

The worst is where a driver drops someone off, and as they leave, they beep their horn. Like seriously, what are you playing at.