I have a pact with the spiders in my house. If I spot them running across the floor or on the ceiling or tucked away in a corner, they're not bothering me, so I won't bother them. If I see one in an inconvenient place like the dinner table or hanging from the ceiling in the middle of the room, I gently relocate them outdoors.

But...if I'm lying in bed trying to go to sleep and I feel one crawling up my arm, it's broken the pact, and it can't be trusted to leave me alone anymore, so it gets a quick and painless death.