When I arrived in Australia, I was welcomed by my workmates with months of anti-New Zealand hazing, mostly about my accent.
“I can’t understand your ixcent,” they would say. “A friend of mine is going trumping in Noo Zilind; what is trumping?” they would ask, and so forth.
I would reply in the same vein: “Which colonist would you expect to speak the Queen’s English better? One who paid their passage to New Zealand, or one who got a free trip to Australia as a convict?”
“Tramping is exactly the same as Bush-walking, only with scenery!”
Reply in proportion and everyone enjoys the banter. Of course, a sense of humour is required. you put it well: “ It is a sort of bonding thing in many ways and it makes for a much lighter working atmosphere. If an Irish person is too formally polite then you know they don’t like you.” That is the same in Australia, probably because most of the Axe-murderers, Highwaymen, Rapists and Thieves transported to Australia in the 18th and 19th Century were of Irish descent.