Humour.

Now we are talking...

Primates fling shit at each other. Then they evolve into humans. (Not quite what happens but hey, speaking to people who think a virgin can have a child here...) Then they carry on flinging shit at each other.

Then some of the semi evolved ones need to see a reason for flinging shit at each other. Then they find a reason. Then the more evolved ones sigh.

Nothing left to do except fling a little shit I suppose...

Hello Sailor!!!