It doesn't seem really logical, and I'm not sure it's ever happened to me, except maybe once as a really young man, but I think love at first sight is possible. Rare, perhaps, but possible. Then again, maybe I've just seen too many movies.
There are times when you can tell a lot about a person just by the first impression they make. Psychics and other 'mind freaks', in my opinion, are able to make their living, doing what they do, because they have an uncanny ability to read almost anyone. Couple that with the fact that at least half the people they read, are going to want advice of some kind based on hokus pokus, whether seriously, or with a certain cautious distance.
Point being is that, I think for some people it's possible. I mean, if you really think about, it's not that far fetched that it could happen. Rare, again, I say, but not out of the realm of possibility. I'm sure timing and place would have a lot to do with it. Love at first site at the bar, I would say, has a small chance, and isn't realistic. Love at first site at a highly specified organization event, where everyone is already of like mind for the most part, more probable, yes.
Attraction, physical, and mental, I really see no difference. It's a ******** distinction, probably largely the result of a society where women are constantly pressured to perform, as far as looks go. I don't view myself as a person inhabiting some sort of body that is seperate from me. I may not always be whatever I look like, paints me as, but what I look like is invariably a part of me. My age and my history is worn into the groves of my skin, my style or lack there of, may or may not represent a varying degree of variables.
So I guess, 'love at first site', might be a case of juding the book by it's cover, however, I think it's possible, in some cases, where it just so happens to work out. Very few cases...
Then, I suppose, there is the fun part of disecting what love really is. On the cynical realistic side, it's probably just the result of an emotional attachment designed specifically to increase the chances of reproduction as well as to maintain a monogomous pair bonding relationship to ensure the apt raising of said offspring.
Guess it just depends on if you are on the one extreme of a hopeless romantic, or the cynical pragmatic realist tournament creature, where sex is just a function like pooping, and relationships are basically just agreed upon levels of trustworthiness to base socio/sexual transactions upon, which will either grow in it's mutually beneficial nature, or fall apart.