Humbug is best known as the dismissive catchphrase associated with Ebenezer Scrooge in Charles Dickens' A Christmas Carol, where it sums up contempt for festive cheer. The Mr Humbug wording turns that familiar idea into a direct nickname for a person acting the same way. Short callout clips like this circulate on soundboards because they are easy to recognise out of context and quick to reuse. It remains popular for seasonal jokes, reaction videos and edits that need a clear, old fashioned label for grumpiness.