I've always found this interesting because nothing about the appearance of a snake has ever bothered me, unsettled me, or made me fearful. They actually look very neat to me, and the tiny snakes I've had the fortune of holding were very fun to feel slithering about in my hands.

Cockroaches on the hand, not scary at all, but I feel disgusted by them.

And large spiders, extremely scary to me, instant fear response.

Cause your nervous system knows what a snake is but doesn't know what a picture is?

There is the theory that a substantive percentage of people have dangerous prenatal experiences with their umbilical chord, as the source of their fear of snakes, and that it can be resolved later in life with regressive therapy. See e.g. ”Womb Surround” by Ray Castellino.

I'm not unsettled by them.