Matt Berry plays Laszlo Cravensworth in the comedy series What We Do in the Shadows, where his pompous vampire character is known for elaborate insults and dramatic outbursts. Effing and jeffing is traditional British slang for swearing, using softened stand-ins for stronger words. Berry's delivery turned the phrase into a popular reaction clip online, shared whenever fans want an upper-class, over-the-top way to complain about bad language or chaos without using an actual explicit rant themselves.