Nikola Tesla and Thomas Edison
Though they overlapped in their interests, Tesla and Edison couldn't have been more different in outlook. Edison was brash and entrepreneurial while Tesla was eccentric, private, and motivated by his humanitarian ambitions. After getting stiffed for his work by Edison, Tesla worked with George Westinghouse to build an alternating current system. Edison, who held the patents on the direct current system, sabotaged Tesla's efforts by publicly electrocuting local animals in a smear campaign against AC. It doesn't get much more evil than shocking kitties to falsely shame the greatest geek who ever lived.