What about the GEO Metro and the Ford Festiva? The Geo Metro was a rebadged Suzuki Swift, and came from Korea.
The Ford Festiva was a cheap German built American imitation of a cheap American built German car...
But my worst ever American honors has to come down to either the Chevette, Maverick or Citation (X-Body), but only because I have personal experience with all of those. Universally, they were all POSs.
But backed into a corner, I would have to go with the Chevette. I had an automatic. No power at all. Bought it used for fifty bucks, and I wuz ROBBED!
Misinformation is a scary thing. The metro was not built in Korea. It was built in Canada thru a joint venture with GM and Suzuki. Early models and the Chevrolet Sprint were sent over from Japan. In general they were good cars. Small and cheap and got 55 mpg. The Festiva is not to be mistaken for the Fiesta. The Fiesta was a German designed small car sent to the US in the late 1970's. The Festiva is built in Korea by KIA.Ford bought it and its Aspire sibling from KIA and sold it thru its US dealer network.Known as the Pride in its home market and in other markets that KIA sold it in. It was originally designed and built by Mazda as the 121. KIA licensed the design and built it for cheap. Problems with it were mostly cheap and extremely thin body panels. Also its 4 cylinder engine was not the longest lived design. Each person has his horror stories about American cars. My family had a Vega...lasted 15000 miles from new. Inexcusable. We owned a gremlin Very fast and well built but not to everyones styling taste. There was no 4 door gremlin built. That was the Hornet which was on a longer wheelbase and came first. The Gremlin was a chopped off Hornet. I would say any mid-70 thru present US made car is junk. We had not owned a US car in years ,1979 chevy the thru a rod at 41000 miles was our last until 1996 when we bought a Neon. Total junk. It was in the junk yard at 48000 miles after three blown head gaskets and hundreds of other problems that were the manufacturers fault.