2 come to mind, the Dragon at Adventureland in Iowa, and TOGO death machine Viper SFGAdv. 3 words acn describe Viper, ow, ow, and ow. Thank god they got rid of that horrible coaster.
The roughest coasters I have been on are: Timberwolf at Worlds of Fun, The Boss at Six Flags St Louis, Viper at SFGA (thank god it was put to rest), and the Manhattan Express at NY,NY casino. The Timberwolf has gotten so bad, that i absolutely refuse to ride it.