Seventh-worst: 1958 Edsel Corsair
Ford's (F) Edsel brand became a symbol of a manufacturer's failure to judge the market.
Not to say every Edsel was bad, but the styling wasn't what people wanted -- the marketing of a brand that allegedly competed with Buick and Oldsmobile was way off and the production was often flawed. Edsel was "the legendary flop of all automotive flops," Edmunds.com said.
Among the problems, Edsel was introduced at exactly the wrong time. The barely remembered recession of 1958 was the most significant recession during the post-World War II boom between 1945 and 1970, according to Wikipedia. U.S. auto sales fell 31% from the previous year, reaching 5.5 million.
Moreover, Huffman said, Edsel was "a completely superfluous car" intended to occupy the space between Ford and Mercury. Unfortunately, "there was no space between Ford and Mercury," he said.
As for the car's design, people disagree on whether it was ugly or beautiful. It may be a think line, but Huffman calls the Corsair "one of the most hideously ugly cars of all time."