Why are people scared of spiders?
I believe I'm qualified to answer this question for the simple fact that even reading the word "spider" hitches my breath and sends chills up and down my spine.
Short answer: Because they're silently creepy, wall-crawling, web-spinning, abundant egg-laying, hell-spawn creatures on Earth.
Spiders are utterly disturbing. Their movement, yet apparently slow and steady, feels threatening to me. Their off-putting fuzzy legs creep up and down one or two at a time, like when I menacingly tap my fingers on the table, except even worse because they make no damn noise. What other animal moves like that!? I never know in what direction its heading, why its going somewhere, if it's even looking at me. They can have four to twelve, beady, blinking eyes. They should be able to see well, but somehow they don't. I can't tell if having poor vision makes them more or less frightening.
Not only is their body movement absolutely terrifying, but their tactics are unfamiliar to me in every way. They can descend on a thin thread until they land right between my eyes and cause me to have a panic attack. They're unpredictable and can jump out at you, at any second, if you dare get a millimeter too close. Will they? Maybe, who knows. I'd argue the fact they may not attack you is worse because at least with most other animals, I know to run.
They lay eggs in a dark corner of my closets and hundreds of their damn babies will hatch and wreak havoc without the slightest bit of my knowledge. They have fangs and most will inject venom in you even when you're not trying to attack them. And their damn webs. They're a beautiful work of nature, but when spiders decide to make a home on your ceiling, you get to watch them capture other insects/bugs, who are visiting uninvited, as well.
They're also intrusive. They seem to come out when it's dark, much like rats. When I turn on the lights in a room (in which I thought was empty), the last thing I anticipate to see is the devil's creation. I mean, a spider.
There is literally no reason I would ever want a spider next to me. I can admit to it being a cool and unique animal, but no, thank you.
Funnily enough, I have no problem with snakes, which are probably a thousand times more venomous. Go figure.