yeah I think it's a fear thing. just like it'll happen to you with water, it happens with spiders for me. my theory is that it isn't the object itself but what we're feeling- loss of control for the water, maybe? and for the spiders, they intimidate the hell out of me and make me feel unclean.
idk I'm really trying to analyze this. there's got to be a reason our minds choose something that scares us sometimes but other times it'll be harmless. Something deeper going on.