When in public and someone else is being obnoxious or annoying to all, get right in front of them or otherwise nearby in line of sight, and stare intently while grinning as hard as I can. This amazingly works to shut up or drive off all types of nuisances - soap box preachers, drunks, arguing couples, loud music or cell phone users... I have shamelessly used this in restuarants, lines, public transportation, etc.
Random misbehaving children get the momma stink eye from behind their parents back. Or absent parents, and stink eye ineffective, a casual comment about store managers or grandmothers or something. Crying babies and crying small children get outrageous faces made at them from behind the parent's back.
and when speeding down our road at the old house got ridiculous, I DID sit in my car, with the fancy Scouting hat on, with a black hair dryer in my hand... amazing how that works.