[Rosie] Hmmm - see what you mean. I thought I'd added the words '.. when there's no-one around' [which might make more sense of the analogy]

I've created a game :-)

Politeness requires that one should try not to make a noise when expelling anal gas. It similarly requires that one should not make a noise upon discovering expelled anal gases. Thus society continues in a mutual agreement to ignore the occurence.

sounds like a lot of heads being buried in sand to me...

My father used to say "you're like a fart in a colander" to indicate uselessness. I don't know why that has just popped into my head or even why I'm bothering telling you lot, but there it is.