To me when I see him clowning around it just gives me a feeling he's not focused. Even in the serious part of his interview he just doesn't seem hungry, driven. I think alot of our US runners are the same. I remember Alberto Salazar in his prime, he just had the eye of the tiger.I wonder what happened.
Salazar looks like Dracula on the cover of his latest book. I don't think he has lightened up much.
Maybe it would be interesting to compare the success rates of runners who like to kid around and have a good time and runners who are always dead serious. I don't think you would find a meaningful difference but maybe that's just my experience.