The thing is, he is a person of considerable intellect that was not funneled into academia when he was young, so it comes as a surprise even to him. If he had not wasted so many brain cells when he was young and alcoholic (and kudos to him for quitting and for telling everyone about his recovery), he'd be working with Elon Musk on world problems. But his mind does shine through in so many ways. I've read a couple of his books. I find him hilarious... and also occasionally dead serious, like his lovely tribute when his father died.
This is also one of my all-time favorites, second only to his very last Late, Late, Late Show. This if your basic "Braveheart" Scots warrior sound:
He was also great on The Drew Carey Show.