The dream part is sort of embarrassingly autobiographical; I (though I) only liked girls until I had a dream about dating one of my male friends, and even though it was somewhat irrational, the feeling of goodwill toward him that it created made me seriously like him in real life. So, it's not actually that far-fetched, although perhaps more likely for a teenage girl than an adult man.

Gah. I thought I fixed that. *goes to edit*