The first stage of love has been called limerence (I suppose because of the urge to right bad poetry). This stage is ALWAYS transient, but is the stage that people always associate with love. http://en.wikipedia.org/wiki/Limerence
its a medically proven fact that the first stage is a form of mental disorder. Its all dirty boxer shorts, fish and chip suppers and arguing over money after the 3 month honeymoon period
Love at first sight's a rare thing (usually infatuation), but it CAN happen. Although I'd vaguely known my husband from social gatherings, for a few years before we actually got together, we fell in love pretty quickly. I've also known others who've "known" from the start.
I thought I was in love with my boyfriend but after the 3 mth I realised I am not. I was in love with the idea of who I thought he was then realised he is not like that at all.
He is a con artist but at least my head is not in the clouds anymore. Needless to say is soon to be a ex bfriend after I get my money back he owes me !!