Cyclists who are so intent on getting a better time on their route tracker app that they disregard everything and everyone else on the road.
The three cyclists, one of which was a 50 year old doctor who were doing the above, who threw a punch at my wife and damaged my car because she stopped at a junction and held them up. Who then bravely legged it when the police were called. So dumb were they that they forgot that they could be tracked on their own app, idiots.