Relatable characters are one of the main ingredients for any movie to work on an audience, and the more flawed they are is a plus. Some of the portrayels are so iconic that we can’t imagine anyone else playing them. There is no Taxi Driver (1976) without Robert De Niro as Travis Bickle,or (for contemporary audiences) no Pirates of the Carribean if Jack Sparrow is not played by Johnny Depp. Both of the forementioned characters (and countless others) are in totally different situations (let alone genres), but we relate to them because of their flaws. In short, they are anti-heroes.
This brings us to Cool Hand Luke Jackson, which is a role that is forever immortalized by screen legend Paul Newman.