There is bad behaviour on all sides - Some out of simply being a twat, and some because people generally do not know how to handle certain things on the road and i just think the best way to tackle that is education.
Shocking things i have seen from drivers include;
Pulling out on cyclists
I have even seen drivers open their door as a cyclist approaches i nan effort to have them off.
Horn blasting at horses
speeding past too close to horses
Shocking things ive seen from cyclists include
Assuming red lights do not apply
Attempting (and failing) to beat 4 lanes of moving traffic rather than use the much safer crossing 100metres down the road
Getting right up a horses arse on a bridleway, and ignoring the riderwhen she informs you the horse WILL kick out, please move.
Shocking things i've seen from horse riders;
Letting your ten year old who clearly cannot ride well out onto main roads on a flighty young thoroughbred (Proceeds to bolt up and down uncontrollably)
Smacking cars with whips despite them passing quite safely and considerately
riding down the pavement despite a clear road next to them.
ambling along two abreast ignoring the traffic behind them.
All of these things could be addressed - For car drivers in the form of additional aspects of the test. With horse riders and cyclists in the form of compulsory riding and road safety tests. I often hear the excuse 'it would be unenforcable' well - No it wouldn't. You could be given an id number to wear in an armband when you ride, or be required to present this in so many days in the case of an accident, like with driving licenses, and fined for not having one. Like with driving licenses.