'D'oh!' became Homer Simpson's signature catchphrase in The Simpsons, which began in 1989, and was added to the Oxford English Dictionary in 2001. Voiced as an annoyed grunt, the line was inspired by older comedy actors and was written in scripts as 'annoyed grunt'. Over decades of episodes, films and merchandise it spread far beyond the show, becoming everyday slang for a minor mistake. Online, the isolated clip is shared on soundboards and in meme edits as a universal shorthand for frustration.