Here's an interesting write up on left handed myths. 

Throughout recorded history, left handers the world over have been the objects of scorn and fear. they have been characterized as outcasts, degenerates, communists and perceived as inferior, clumsy, unlucky, sinister and even satanic! the latin term for left handedness is "sinistral". the Devil is most often depicted as being left handed. Buddhism believes that the road to Nirvana is said to split into 2 paths, the left "wrong way" and the right "the path to enlightenment". In early plays (as in theatre plays), villains always entered from the left side of the stage. 

interesting huh? =)