We idealize love from a young age. Disney movies ingrain in us the fantasy of romanticized fairytale love. We enter the hormonal turmoils of adolescence with this notion and discover the not-so-charming reality of courtship. Many people enter into marriage with this fantasy, and divorce rates reveal the honest truth.
Don't get me wrong; I believe love exists, but it's certainly not this storybook romance that movies and antique rhymes make it out to be. It is sometimes hard to give up a fantasy even with a hard dose of reality. Many people still cling to childhood wishes, no matter how fairytale-ish or delusional. As we get older and more immersed in reality, we start losing the idealism we've held in many aspects of our lives. We learn that the girl at the fast food place is a real person; we discover that our math teacher has a life outside of the forty-five minutes we see him each weekday.
I see theism in this respect. Belief in God is a fairy tale. The fantasy stories of living after you die in a palace made of gold and mansions full of ever-virgins are just that -- stories. Christians idolize Jesus as well, clinging to the idea of a once-lived perfection of humanity. These ideas of perfection and fairytale love are delusions and wishes of our imaginations.