Stimulus/Response

I have made an observation of human behaviour. So far I have only observed this in females of the species, but it may equally apply to males. When a girl is just on the verge of entering a romantic relationship, she becomes way more friendly to everyone else, including people she might have avoided previously. I also have a couple of half-baked pop-psychology explanations:

• She may believe she is keeping the secret by behaving in a more friendly manner to everyone rather than just her prospective partner.
• Her system may be flooded with positive hormones, bringing about an involuntary goodwill to all people.
• She may (subconsciously) realise that she's about to drop out of many social circles for a little while, and is pre-emptively making up for it.

Mokalus of Borg

PS - Whatever the explanation, I have seen this to be true on a few occasions now.
PPS - I have yet to correctly interpret it as it happens.