I have tried to address the source of my fear. I guess a few things bother me.
-They are hard to track because they are generally small. I can't see where they are going if I want to kill them.
-Hairy, beady eyes, eight legs. I guess the combination of physical features is intimidating and gross looking even if it was a giant robot spider.
-Like any bug, I don't want it to crawl or reproduce on me, or lurking around my living area. Just like I would kick out any non domestic animal from somewhere I was staying.
-It still could bite, even if it's not poisonous. Still gross to think about such a repulsive menace piercing your skin with its fangs.