i think it's more about the things we learn about a person right from the start, from body language, how they carry themselves, etc. like a first impression. we automatically make these assumptions in the first few seconds of meeting any person, and i guess if you talk to the person and they made a really good first impression you cant ever remember not liking them. put it this way... if you saw someone at a party or something, and you think its love at first sight, try to ask yourself "wold i die for this person? right now?" the answer is probably no, although there are people who would do this for anyone.
also, i dont think the love for god is like unconditional love, there are too many agnostics, atheists, other religions, and people who hate god for not blessing them or some crap.