Post 1950 american cars are, in general, ugly.
From time to time, Detroit surprises us with a beautiful car but, unfortunately, for these rare cars the evolution is from beautiful to ugly. Think of what happened to the 1965 1/2 Mustang. Glad that Ford did'nt have enough time to mess up with the CSVT.

They did have time though to decontent it ...
As for the ugly american cars (the list is long), their normal evolution is from ugly to ugliest. The Pontiac Aztec however has been designed and produced directly in its ugliest state !