My reaction isn't nearly so strong. If the spider is in an innocuous place and doesn't look jumpy then my first inclination is to look away and pretend it's not there. But I try to force myself to sit there and stare at it for a while, and scream out "SPIDER! There is a SPIDER! Spider. Spider." in my mind, or half-shout out it if I'm sure no one is around, to train myself to not flinch away from things that are unpleasant, and to keep my mind from getting into the habit of thinking that if I ignore something it will go away.