It's the same reason that people see Jesus in the grain of the doors, or the last supper (like da vinci "envisioned" it) in the clouds.
It's not just that we need to believe in more than ourselves, but because we find meaning in being a part of something greater than ourselves.
It's the desire to experience something incredible, magical, special.
We don't just want to believe, we want to know that we're right to believe, and so.. we seek out "Proof".
If we see a man who tells us he's the messiah, Jesus reborn, or whatever, and he smiles at us, calls us his children, and offers us a connection with god, it's easy for us, even if we're rational, intelligent people, to be so enamored with the thought that we can be allowed a physical touch representing the love of god, that we can be taken in.
Ofcourse the knots in the grain of the door are just knots, and not the eyes of Jesus, but that doesn't stop us from wanting to see eyes.
Sometimes I feel a little touch of envy for those that see magic in the world. I want to see the magic too. I want to be amazed and all that. But when I look at the door, I just see knots in the grain of the wood.