When I was growing up the words 'spastic' and 'spaz' (more commonly pronounced 'spa' with a kind of glottal stop at the end) were part of our rich palette of insults. Even back then they were mildly frowned upon.
Slightly surprising, then, to hear Tiger Woods liken himself to a 'spaz' the other day, not least because I'd thought this was a uniquely British pejorative and because it seems to breach some of the notions of political correctness that Americans hold very dear.
In the Guardian meanwhile, John Harris is complaining about the current vogue for sneering at chavs. His complaint is not so much about the word itself but of the contempt it implies for working-class people generally. Others argue that 'chav' isn't a class insult at all but really describes a particular type of vulgar, threatening, selfish behaviour that the 'decent' working classes find as abhorrent as the rest of us.
I think Harris is right. Chav has replaced terms like nouveau riche and counter-jumper as ways of putting down members of the working class who get their hands on a bit of cash (or act as if they have). They may have money, is the message (spoken or unspoken) but that can't buy taste...
Being poor in Britain these days is viewed as a moral failing but getting ideas above your station is far, far worse.