21: Chevrolet Monza
When the fuel embargo of the 1970s hit, consumer appetite for high-performance gas guzzlers depleted overnight. GM had to act quickly to bring new fuel efficient car models to the market. The Monza design was based on the Vega, and the resemblance is uncanny. The Camaro of the time influenced the rear taillights (via EP Auto). The 2+2 design was smart in theory, but the rear passenger leg room is non-existent. Cargo space was nonexistent in the Monza even though it had a hatchback.
Critics universally pan the Monza whenever a history of Chevrolet cars is brought up. There were other awful cars from this era including the Ford Pinto, but the Monza took the top prize. GM would spend decades trying to perfect the compact car, only to exit the passenger car market in the 2020s.