Mark Buehrle.
Anyone who has ever dealt with him can back me up on this. Guy is like a 10-year-old in a 29-year-old's body. And I mean that in the best way possible.
Last night, he gets a standing ovation from the crowd and he just breaks out grinning from ear-to-ear. You don't see that too often. But that's him. He had to get reprimanded by Kenny Williams a couple years back for doing belly slides on the tarp in a rain delay. Oh, and he occasionally brings a lifesize cutout of Nick Swisher into the dugout to celebrate when Swisher does something good.