Often the most colorful use of language is by people fairly advanced in years. For me, this lends a sense of urgency to finding out where some of that usage came from. The fear, I suppose, is that something valuable will be irretrievably lost if phraseology is allowed to die off with its users. Conversely, some expressions become utterly senseless once their currency is depleted. That said; Where did the expression "Fighting like (the) Kilkenny cats." come from? Other than geographically-speaking, that is.