Why does the moon have a face on it?

The moon does not actually have a face on it. It just appears to because of the sun

-- answer --

The moon 'appears' to have a face because we humans look to see patterns in things. it is part of how we cope with the world around us. In our pre-history it was important that we recognise a face hidden in trees or other surroundings as it might be an enemy or a predator.

Trying to see a face was crucial to staying alive.