i have the worst, most blinding, road rage ever.
when i did drive, i would get incredibly angry at anyone who chose to drive like an idiot.
oftentimes, i would get them behind me, and launch a handful of pennies out the window. when a pile of pennies hits your windshield, you tend to freak out at least a little bit.
as far as bikes go.... i don't really want to get into some of my more "colorful" antics.... but they include socks w/cue balls in them, u-locks, spray on paint stripper, and following people home.

i'm not particularly proud of some of the things i've done.... but if somebody is going to be a complete jackass and disregard my safety, or the safety of one of my friends, for no reason whatsoever, then i see no reason why they shouldn't be taught a lesson. granted, i could mess with the wrong person and get shot/etc., but it's just as likely that today could be the day that they ****ed with the wrong person.

i wouldn't worry about macing someone. if you live in a city, you can get away with retribution all too easily. standing around macing them, and then trying to justify it to the police, is not going to end well for you.