Argh, I went to my fiancée's work Christmas meal a few years back and the wife of one of her colleagues was kicking off to the staff about the portion size of the soup her husband had ordered as a starter.
Her justification was that he's vegan and needs the extra calories!

It was so awkward as the staff were insisting that was the normal portion size as it was a starter and she was insisting they take it back and tell the chef to fill the bowl!
I was cringing inside out. My other half made sure the serving staff got a generous tip from the group.