My dad's single greatest skill would probably be optimism. More specifically, a unique breed of always knowing things will work out, that you can do anything and that everything is good.
It's a skill that helped him to have all sorts of adventures in Chicago as a boy, to coordinate troop shows for the army, to create his own successful film company in San Francisco, to have a sheep ranch in Half Moon Bay, to own multiple sailboats and planes, to go to medical school in his 40's, to have me when he was 50, my sister when he was 53, to have a successful second career as a psychiatrist and to zip line across the Costa Rican jungle in his 70's.
I hope that I've inherited some of his optimism...I certainly got his nose, fine brown hair and chicken legs! Even a small dose of it would go a long way. Happy Father's Day!