The moon seems smaller when up in the sky and bigger when on the horizon. I was surprised to learn that the real cause is still disputed.

The moon illusion

They are apparently there to help you see the keys to make it easier to type. If you can type already, fold them away — it’s better for your wrists to have no bend.

Fold away keyboard feet

I still find somewhat remarkable the complexity in a simple button on the web. These are just 6 common states that may each have their own appearance and behaviour.

Common button states