2. Gyp Rosetti
When New York sociopath Gyp Rosetti's reign of terror was finally brought to a screeching halt in the Season Three finale, everyone – not just Nucky – breathed a huge sigh of relief. Just look at this guy the wrong way and you could find yourself drenched in gasoline and lit on fire, while Gyp numbly stares you down. A second-rate gangster consistently emasculated by his wife, daughters and Joe Masseria, Gyp's hotheaded behavior was understandable, although certainly not forgivable. His life on the Boardwalk didn't last more than 12 episodes, with him getting stabbed in the back – literally – by his right-hand man, Tonino Sandrelli. But Bobby Cannavale's stellar, frightening performance solidified Gyp's exalted place in the series' history as he picked up a Best Supporting Actor Emmy (the only acting award given for Boardwalk to date) earlier this fall.