I 'lost religion' at such a young age that it's arguable whether I ever really had it so I'll have to take your word for it that losing religion is an example. I don't feel I lack many of the things that people sometimes say they fear they will lose if they lose religion however.

I think janos makes a good point that the hormones example you describe is more a case of allowing your thoughts to distract you rather than a problem of possessing knowledge. Romantic warm fuzzies can be disrupted just as effectively by thinking too much about mundane things like work or the day's chores as they can by thinking about the role of hormones in creating physical attraction.