Moving into the top 10...
10. Pontiac Aztek
The Pontiac Aztek was launched in 2001 with the tagline "Quite possibly the most versatile vehicle on the planet." Too bad, because most of the world population thought it was the ugliest vehicle on the planet. The 1999 Pontiac Aztek was acceptable by most standards-it wasn't pretty by any means, but hey, it looked rugged and tough. Unfortunately GM chose its minivan platform for the Aztek, which gave the car weird proportions. Then designers fiddled, played, and cost-shaved the design until the rugged concept was turned into a laughing stock of epic proportions. The Aztek created more ridicule for GM and Pontiac at a time when GM was already a laughing stock worldwide, and sales were way below expectations-GM had high expectations to sell 70,000 cars a year, but only 27,000 moved out the door every year. Too bad really-under that ugly shell was a pretty competent crossover, and people that bought it loved it-but the looks kept most customers out of showrooms.
9. Ford Mustang II
The first Mustang was a American legend-it was fast, it was hot, and it handled well (well, for American cars of its time.) So, in reaction to the oil crisis, Ford gave us the "wonderful" (chuckle) Mustang II. Apparently Ford decided to slap a new body on a Pinto platform was a great idea. Engine choices began with a 88hp inline-4 to the Cologne V6, which made 105hp. Ford gave us a V8 in 1975, which made 122hp...impressive, isn't it (insert sarcasm here.) This rolling turd was powerless, ugly, and poorly built-the structure of the car was ludicrously fragile and fell apart when the car approached anything near speed-but no worries really, unless 25mph is "fast" for you. Those really were sad, sad times.
8. Chevy Citation
The FWD X-Body cars (Chevy Citation, Buick Skylark, Oldsmobile Omega and Pontiac Phoenix) were launched in April of 1979, replacing GM's old RWD compacts (Chevy Nova anyone?) and promised a revolution in GM's lineup. Yeah, it was revolutionary all right, when you consider that GM's whole lineup was complete s**t back then. The car suffered horrible torque steer due to its FWD design-in fact, press cars were modified from stock to hide that fact. The rear wheels locked after braking, and the car had classic 70's build quality-in other words, if the car fell apart after you drove it off the lot, don't be surprised. A press car was badged as both a "Super Sedan" and a "Super Coupe"-seriously, do GM factory workers ever inspect the cars before they come off the line? The Citation was also probably the car with the most recalls ever, some even issued after the car was completely forgotten. But buyers saw none of that coming-GM moved a few million of these pieces of crap out the door.
7. Caddy Cimarron
There's nothing wrong with a smaller, sportier Caddy-in fact, I would say Cadillac needed a smaller and sportier model back then. Not much wrong with badge engineering either, as long as it's done right. Like, uh, actually trying to make a luxury car. The Cimarron wasn't a smaller and sportier Caddy, it was a super-overpriced Chevy Cavalier with Caddy badges and some leather. Heck, for the most part you won't be able to tell the difference. The Cimarron had the same 88hp I4 that the Cavalier had mated to a 4-speed manual or a 3-speed automatic with a slightly modded interior. The whole thing cost $13,500 (if you need an idea, the Cavalier was $4,500.) Fortunately, this rolling embarrassment to Caddy owners was succeeded by the Catera (umm, Opel Omega to you Europeans), which wasn't a good car by any means, but still a lot better than the Cimarron. The Catera was succeeded by the CTS, which was a excellent performer and proof that Cadillac finally got it right.
6. Caddy Fleetwood V-8-6-4
There's nothing wrong with shutting down cylinders to save fuel-in fact, many modern cars shut down cylinders when full power is not needed. In other words, the V-8-6-4 was a V8 on the highway, became a V6 when it reached speed and became a V4 when cruising. Sounds great, right? The problem was that the technology to do so wasn't near ready back then. The system worked by altering the rocker-arm fulcrum so that valves were kept shut by springs. Too bad the electronic system that made this work was broken most of the time, so in reality these cars spent most of their time in the shop instead of on the road. Even when the V8 was running on full power, it made a mediocre 140hp. Most customers asked the dealer to disconnect the entire system so the engine became just a regular V8. And that was the last time many of them ever entered a Caddy showroom.