Pareidolia is not just a simple mind trick making you see funny faces on things when there actually are none. It's no sign of psychosis coming your way either, but rather a quite complex, pre-historical self-defense mechanism. Yes, it's true, seeing unlikely faces helped our ancestors survive; if you presumed that the rustling bush has a saber-toothed tigers' face hidden behind the leaves, chances are you'd run and save yourself if there actually was a beast lurking in the greenery.