If it's worst character for acting then the prize has to go to the bit parts David Chase's daughter got in a few episodes. She was the friend of Meadow Soprano earlier in the series and got a cameo in the finale I think. Always looking at the camera.
Best, there are too many to name. Paulie Walnuts is the first that springs to mind. Him and his tourettes LOL
Best, there are too many to name. Paulie Walnuts is the first that springs to mind. Him and his tourettes LOL