I have it too. Moon (Sag) conjunct Neptune (Scorpio) all in my first house.
Neptune is also conjunct my ascendant.
We talked about this a bit in Elina's thread here just recently:
http://www.astrologyweekly.com/forum/showthread.php?t=31315
Staryeyed, yes, I related to exactly what you said. I can pick the vibe in a room almost instantly. One "scan" is all it takes. Absorb it in like a sponge. Which shouldn't be surprising to us because having this making us highly intuitive and psychic so of course we would absorb these energies. I think it is sort of cool - I can spot the liars and the fakers spot-on usually.
My friend has Scorpio Moon and Neptune conjunct her ASC. I think it gives her an alluring almost dreamy quality(according to men) but she also doesn't see herself clearly. Meaning, her perception of things, mainly when it comes to who she really is, is murky at best.
Vista
I have been told this also by men. I read this about it:
http://www.astrozoom.com/astrologer/astrology/ascendant-conjunct-neptune/
People will see their "fanatsies" in you apparently. Men tend to see that in me. I attract the weirdos.
My son has moon

conj Neptune

in Saggi

in 1st house and this aspect can 'charm the birds out of the trees' as well as pick on vibes......along with the typical 'catch me if you can' saggi traits of good humour and needing the freedom to socialise
Haha! I do this too. The link above also states that Neptune conjunct Asc does use their charms like this. Nice to know I have some power.

I do realize when I do this too. If I want something, I will use my charm and grace to get what I want.
Here is one the descriptions I have for Moon conjunct Neptune:
" Conjunction Moon - Neptune
Positive aspect: She is kind and sympathetic, with a strongly compassionate nature. When in love, she is usually very devoted. In fact, she is devoted by nature, not only in matters of the heart.
There is an unmistakably compassionate and understanding side to her nature. She has a natural affinity to music. While everyone enjoys music, people with Moon in harmonious aspect to Neptune respond to music as a vehicle to heal, relax, and to uplift the soul. Naturally perceptive, without even trying she tunes into the feelings of others, and the mood of her surroundings. There is a distinct emotional need to escape into the world of imagination, and to withdraw from others at times when she needs to re-center herself, largely because she tends to "take in" a lot of mixed energies from her surroundings. Strong and sudden "feelings" and hunches can overcome her. More often than not, her intuition is correct, although her imagination is also powerful and she can read too much into a situation as a result. Some laziness is associated with this position. This stems from a natural timidity and sensitivity that is apparent from youth. She may have been labeled "shy" in youth, and family members or friends may have jumped in to "save" her from situations that required boldness or aggressiveness. Thus, passivity was accepted and, as adults, she may be less experienced than most when it comes to reaching out or going after what she wants. "