"I Wasn't Kidding" was written by Andrea Martin and Adrian Austin. Inspired by Martin's wish to use the beat of the Womack & Womack song "Baby I'm Scared of You" (1984) in a new "break-up song,"[1] much of the lyrics were penned by Austin.[1]
Billboard felt that "Stone conjures the 1980s with the booty-bumping" song and declared "I Wasn't Kidding" a "fun track, a stellar vocal and deserving entry on Stone Hits: The Very Best of Angie Stone.[2] South African news website Independent Online called the song "a great old school jam."[3]