What is it with green screen videos that are shot from the waist up, that people have to take their pants off?

I did enjoy that Dan, found myself singing along, and DANCING what's more. How do you do that? I get the feeling you've been doing this sort of thing for some time now.
There's no fear or self consciousness in your performance.
I don't think there's any need to take your pants off to prove that to us, it just shows. :)