These do make some of the best "villians."

An extreme example of this comes to mind. There's a long-running science fiction series by David Weber that includes a war between two nations, one of which goes through about three changes in leadership during the course of hostilities. By the time the last leadership group assumes control, the purpose behind the war and the reasons that it continues have been lost - both sides are being led politically and militarily by well-intentioned people, with only a few destroyed diplomatic documents and one totally random death keeping the two sides from seeing eye-to-eye.