On a conceptual level, I have nothing against spiders. They're a lot better to have than not, since they keep other crap away, and they generally keep to themselves. I'd probably be the kind of guy that puts them outside whenever he finds them.
However, this is prevented by...
Arachnophobia. Which I've got so bad that any spider I see I either run away from or try to kill with the most excessive use of force possibly, usually before I realize it. I am not joking in the slightest when I say that I was once walking through my room, saw a rather big spider on the wall, and, out of reflex, threw my goddamn desk chair at it.
The very sight of them gives me nightmares, to the point that even looking at the spider-bro comics higher up the page made me curl up into a ball on my chair and inspect every corner of the room from my chair to make sure no spiders are present.
I'm pretty sure me and spiders could be pretty good friends, but every time I see one my goddamn ancestral memories kick in and make me murder all arthropods in the vicinity or just get the fuck out of there.