This always makes me think. Cockroaches don't bite, are not venomous, basically can't do us any harm. I'm not afraid of wild dogs, spiders, tarantulas, scorpions, snakes, wolves, hyenas, wild hogs, bears (encountered them all) but I might actually scream if I get surprised by a cockroach.

I think this collective fear of cockroaches that we have cannot be without reason and must have an evolutionary reason.