Paul Newman is a middle-aged guy, definitely over 30--but Cool Hand Luke trusts him--and asks us to do the same. But trust him to do what, to be what? He is a charmer, a movie star in chains--George Kennedy closer to type, sweaty without looking like he enjoys it, his mouth open because he's breathing so hard. But Luke smiles so that you'll love him, believe him--trust him. He is a con in more ways than one.
And the most important part of a con game is that the mark enjoys it, smiles all the way. And this is the triumph of the movie: placing Newman in that role, letting us in on it--almost--but at the end as much to blame as Luke's God, the Old Man he shouts at like a cool Job. The road-gang Boss knows all about failure--and so does Luke; but he doesn't trust it, just himself, and gives us this truth about failure: it carries on without us, so we might as well grin, and croon to our plastic Jesus, swallow each hard-boiled egg like it's the last one we're ever going to get--because of course it just may be, can never tell.