Witnesses say he was rude to the waiter. Gilmore also came up with some weird statement about knowing John Key, and how the waiter could lose his job.
The waiter's crime? He had refused to serve Happy Gilmore more wine.
In apologising after the event, Gilmore offered up the weak "our group was a bit boisterous" excuse.
This prompted a member of his four-person group - a lawyer - to come forward and say, "Hang on, mate, what's this 'group' thing?"
Apparently Gilmore's behaviour had been so bad that the lawyer had apologised to the waiter.
I doubt Gilmore has ever worked in the service industry, where the customer is always right, but the waiter is also in charge.
While I was a barman working in London, most punters I served were salt-of-the-earth locals.
But in a country with a class system, you'd always strike one or two who viewed you as "the help".
My personal worst experiences involved an actor who walked into a closed pub and demanded a drink, and a meeting with my boss because I couldn't serve him, and a child screeching "I want sorbet" at me in a country club I had the misfortune to work in.
At the time, I thought sorbet was a town in Spain, a country I'd have much rather been in.
As for Gilmore, Key is open to investigating the incident if someone complains.
Every waiter and waitress in the country should demand an investigation.
Key already has sufficient grounds to consider that he has an MP on his hands behaving in a manner unbecoming of an elected official.