I can catch snakes with my bare hands, but why am I so afraid of cockroaches and spiders? :(

If I confirm that a snake is non-venomous, I can catch it with my bare hands. As for rats, they are too dirty to catch by hand, but if there were a justifiable reason to do so, I could. But with things like cockroaches and spiders, I can't even go near them. Why is that? :(