On seeing this thread, I just figured out something that has tugged at me for a long time. Adam's smile and Tiger Woods' smile are almost the same.
At times, they each look a little sheepish, kind of a modest expression, and at other times they both look like the cat that swallowed the canary. As in "I'm the world's coolest bass player" and "I'm the world's greatest golfer" but of course neither would come out and say it.