Here's a thought for you.

Why do we put our poo in a toilet?
Because putting it somewhere else than where we live and play is more sanitary, therefore more healthy for us.

Why is it healthier?
Because there's much less of a chance that the poo will rise up and eat us alive, so to speak.

Why's that so good?
Because we want to live longer and healthier.

Why?
Hmm...