At breakfast asked my wife when everybody started using the idiotic phrase "back in the day"

So I was delighted at finding this in the Urban Dictionary:

Urban Dictionary
Back in the day

Completely meaningless phrase which has gained inexplicable global popularity. It's an incomplete thought: Back in what day? It's a redundant way of saying "Once, I..." or "I used to..." and adds words without adding any extra meaning. Similar to the equally pointless "at the end of the day..." popularised by English soccer stars.