Did you say you've been mugged three times? Oh my...
Perhaps you're "coping threshold" is much more sensitive because of this? The social worker in me is playing with this at the mo., so I'll just throw my thoughts out there...
I think we all have a continuum of tolerance in regard to public nuisances, whether it's loud music, loud people, public drunkenness etc.and so forth. Some folks put on their music/read a book and slip into their own world. For others, this process is much more difficult, maybe because they are preprogrammed to be supersensitive (are anxious, have panic attacks, other emotional/physical "ailment") or because certain life events have made them that way (mugged three times. eek.)
If I were to brainalize myself (and lordy have I:), I know
I'm supersensitive.
1. Because I'm claustrophobic
2. Because I get panic attacks
(And, yes, as a sw, I have dealt with these issues professionally. Yet they still haunt me from time to time.

)
And, while I've never been mugged, during my time as a sw in West Philly, I had a number of run-ins that have freaked the bejebus out of me. One day, I literally was running down the street from a man hopped up on something or other and just made it to the trolley as it was pulling away. Freshly freaked out and predisposed to panic attacks, I sat down, felt the heat of the car envelop me, became dizzy from the "normal" smells and sounds of the people around me, and I had a panic attack. Right there. Awful, awful.
Anyway. Don't want to hijack the thread, but I'm sensitive to the fact that your life experience, particularly the muggings, may have made you more sensitive to the kinda things that many folk take for granted. Your person was violated (it was), and the anger you felt toward your attackers may never have gone away completely. That may be why you get so angry, so quickly. You want to make right those past injustices. Justice shall prevail!
Anyway, back to present. I have to ride public transport (take that, panic attacks!) and you have to ride public transport (take that, obnoxious kids!). Since we both seem to be highly sensitive to different features of public transportation, we both need coping mechanisms, right? You just need to find the ones that fit you. (And you might want to talk to someone about those muggings, girl.)
Lastly, lastly, I promise! If you see something happening on the bus that is illegal and it's happening all the time, advocate for yourself and your fellow riders by contacting the bus company. This may help you to regain a sense of control. Good luck!!!