Because their knee grows.
Afrosclerosis
Because it's the only time a black man can tell a crowd of white people to put their hands in the air.
Ask Jozsef Barsi.
Because when they are kids their mothers always tell them: "If you grow up you have to work" *Translated from Italian hope it makes as much sense as there
Me to instructor: See what I'm up against
Because he had no knees
Clive, usually.