In humans, humour is a debugging process, which is fundamentally rational. The very fact that a statement can be correct or erroneous is the basis of language and therefore education and social evolution.
> there are hardly any fundamental differences between humans and other animals
Evolution is true. But... the ESA and NASA have sent a space telescope to a stable position at Lagrange point 2, and the PRC has a rover exploring the dark side of the Moon.
Humans do have greatness.