On the racism thing, I quote, "hah, especially Asian guys with glasses, so they can read English better!" as they were leaving the bus. It was at that point I reached critical mass, but thankfully cooled down.
I don't get it that often, but that's because everyone who has encountered me knows that I generally have a command of the English language far superior to theirs, or that I can beat the crap out of them for any intentional racist remarks.
I haven't gotten much racism from strangers, either, but if I do I'll start reacting to it. This is Australia under Kevin Rudd, anyone who decides to be racist doesn't deserve to be part of the nation. Funnily, I'd still rather defend someone else than myself.