Probably the #1 reason I will only bike on trails and my nehborhood. Too many punks out there looking to have fun at sombody esles expense.
I was biking to work one day as a kid and sombody thru a baseball at me going close to 80-100mph and to this day I have an injury from it where it almost shattered my xiphode process (where your 2 rib cages connect) it knocked my off my bike and I couldnt breath for like 2 mintues and was sore for weeks.
I dont road rage, but even latley driving on the road has been so bad I just want to have like those big marbles (crushers we called them as kids) to check thru sombodies windshield to teach them a lession about running stop signs or cutting me off so close that it nearly removes my bumper... but then I would be no better than them... and knowing my luck id be in jail/prison.