Now mellowcat is up in arms about the the expression “bah humbug”. Somehow the two exclamations have been conflated into a single phrase. Let’s check back and see what Ebenezer Scrooge actually said when his nephew wishes him a Merry Christmas:
“A merry Christmas, uncle! God save you!” cried a cheerful voice. It was the voice of Scrooge’s nephew, who came upon him so quickly that this was the first intimation he had of his approach.
“Bah!” said Scrooge, “Humbug!”
He had so heated himself with rapid walking in the fog and frost, this nephew of Scrooge’s, that he was all in a glow; his face was ruddy and handsome; his eyes sparkled, and his breath smoked again.
“Christmas a humbug, uncle!” said Scrooge’s nephew. “You don’t mean that, I am sure.”
“I do,” said Scrooge. “Merry Christmas! What right have you to be merry? What reason have you to be merry? You’re poor enough.”
“Come, then,” returned the nephew gaily. “What right have you to be dismal? What reason have you to be morose? You’re rich enough.”
Scrooge having no better answer ready on the spur of the moment, said “Bah!” again; and followed it up with “Humbug.”
So, if you’re unhappy with the poor quality of refreshments at the holiday office party, you can say “bah!”. If you don’t believe there’s going to be a holiday party, you can say “humbug.”