But the situation soon turned even nastier, with Mr McDonagh falling to the ground and grabbing an officer after being asked to leave the premises, news.com.au reported.
As he was taken away by police, he also spat in an officer's face.
According to Metro, Mr McDonagh, a finance worker, left a work Christmas party early and was meeting his wife to celebrate their anniversary before popping into McDonald's for a snack.
He claimed to have consumed six cans of beer before he reached the restaurant, with the incident occurring at around 10.30pm on so-called "Mad Friday" — one of the busiest nights of 2018 thanks to the large volumes of work Christmas parties held on that date.
Mr McDonagh admitted assault by beating of an emergency worker and being drunk and disorderly in a public place at Manchester magistrates court recently.
He was given a 12-month community order as well as a £190 ($AU342.92) fine and 120 hours unpaid work.
Prosecutor Paul Sumner gave fresh insights into the bizarre incident.
"Police informed him that his food order being incorrect was not a valid reason to call them and they requested him to leave," he said.
"They tried to escort him out of the premises, he's fallen to the floor and attempted to grab hold of the legs of the officer.
"The police then were able to hold the defendant by his arms in the scuffle and escort him out of the store.
"The officers were struggling with the defendant and whilst they were doing this, he spat in one of the officers face. He was arrested for being drunk and disorderly and assaulting an emergency worker."
But defence lawyer Claire Parrot argued Mr McDonagh's actions were the result of his serious food allergies and said he was "embarrassed" by his actions that night.
"One thing that wasn't clear is that it wasn't just an argument about the order being wrong, the defendant has severe allergies," she said, according to Metro.
"He specifically asked for something to not be in his food and it was. That is how this started. "Of course he now realises that this was not a police matter. He called them as did the McDonald's staff.
"His memory of the incident isn't complete but he was quite clearly utterly embarrassed and ashamed. This was not a planned attack on the officer, he says that he's not a violent person."