the moon has a massive effect on us. look at the huge effect it has on water... ie the sea. humans are 70% water and our brains are pretty much like a water melon. so it is perfectly natural for the moon to effect us.
we have been conditioned over many centuries to forget about this. so thats why it seems strange that the moon might have an effect on us. many countries celebrate the full moon. i always feel a bit crazy on a full moon and i expect a bit of crazy behaviour from my friends during a full moon. its as normal as being cold in winter, not being able to see at night ...etc