I've had a lifelong love of language, and an interest in etymology as well as slang. Not long ago I read a fascinating article on cockney slang, in particular on everyday words that had their origins in cockney slang. Unfortunately I didn't bookmark the article and I haven't been able to find it again.
The book I'm reading at the moment - Words Fail Me, by Hugh Lunn,(subtitled "A journey through Australia's lost language") - is partly infuriating because while it showcases a lot of old sayings and phrases it doesn't always give their origin. It's still a brilliant collection, all the same. Some of the sayings have made me laugh, while others I can actually remember and there are some that I still use today, so not quite as lost as Mr Lunn thinks.
When was the last time you told someone to "go dip your left eye in hot cockie's cack!" when there was "a bit of a shitfight in the offing". Have you ever described someone as being "ugly as a hatful of arseholes" or "so low he could walk under a goanna with a beer gut" or said "I've seen better heads hanging out of cattle trucks"? Or even "that bloke would give a dog's arse heartburn!" Have you ever told a noisy child to "stop doing the dance of the wounded wombat!"? Just some examples of the pithy sayings in this book. Apparently it had a predecessor, Lost For Words by the same author; I'm going to track it down too.