Worst Car: 2007-2012 Nissan Sentra
To say the Sentra simply has no redeeming qualities at all would be very generous. The engine is terrible, the gearbox is terrible, the interior is made out of the cheapest shit I've ever seen, and it looks almost as dull as a Toyota.
Disappointing Car Everyone Else Likes: 2003-2009 Mazda3
Holy crap, where do I start with this thing? It's ugly, the interior is atrocious, and the powertrain options render it impotent in any market. The 2.0L was too gutless to be considered, and the 2.3L got awful fuel economy for its class. The sad thing is the 2nd generation isn't that much better.
The "WHY????" Award: 2008-2011 Ford Focus (North American)
I cannot, for the life of me, understand how or why this car existed. Not a single panel on it is related at all to the neighboring panels, giving it one of the most incoherent styling designs I have ever seen. The Pontiac Aztek had a more cohesive design strategy than the Focus. As with many America-centric cars, it is a huge pile of crap made out of smaller piles of crap. They should've skipped this abortion completely and adapted the global Focus a few years earlier.
Worst Crossover/SUV: 2009-present Kia Sedona
Drove this as a loaner while getting my mother's GMC Envoy fixed. If this is any indication as to the "new and improved" Korean quality, count me out. The interior trim LOOKS nicer than years past, but it still feels like something out of a cheap cookie tin. The 4-cylinder engine had no ability to move the thing, and had no business being there. The 5-speed automatic was no help, as it seemed like entire sections of the powerband were just missing due to the terrible ratios.