I don't mind spiders when they're living outside. I don't mind watching them spin their webs; I'll even go and watch them work and admire the finished results.
But what is guaranteed to give me the willies and make me run away shrieking is a decent sized spider in the house. When I was pregnant with our 12 year old, my husband and I found a hunter spider the size of a bread plate crawling down the side of our couch (we lived in the UK at the time and had the screenles windows open. The spider lived in the rose bushes outside the window and decided to come in and introduce himself, apparently) and spent half an hour arguing over who should kill it. In the end, I sprayed it with AquaNet and he hit it with a shoe to make sure it was dead. I swear that's why our son had hair when he was born.
So anyway, I don't like spiders much. All my kids know this, yet they still do stupid things like bring spiders into the house to show me - like my 12 year old son just did. He's got 2 big Wolf spiders in a tupperware container and he shoved it right under my nose to show me. I squealed like a little girl and almost kicked the coffee table over trying to get away from them.
Now I've got the willies to accompany my nausea. Great.