 Just purely out of stupid self-indulgence.However, Joel did feature synthesizers on subsequent albums, including "Turnstiles" (1976), "The Stranger" (1977) - as credited in the liner notes and there is a Mellotron on "She's Always a Woman" - "Glass Houses" (1980), "The Nylon Curtain" (1982), "The Bridge" (1986), "Storm Front" (1989) and "River of Dreams" (1993).Other instruments include a pedal steel guitar and drums, the latter of which are played with drum brushes.