I am a male. When walking around my college campus, like most people, I make eye contact with many males and females. Males generally immediately look away and females do the same. However in some occasions, females give a tight lipped smile, not showing any teeth, and I always wondered what this was.

In my opinion this could mean two things. One: She thinks I have found her attractive or thinks that I have fixated my gaze towards her and respectfully and politely declines the advance with a smile.

Two: she has made eye contact with me, and finds me attractive and presents a smile, though tightlipped, to show interest.

What bothers me the most is the tight lippedness of the smile. You can generally tell whether a person is offering a real smile with their eyes and how they curl along with the smile. However, this is difficult to monitor in such brief instances. And more so than not, a tight lipped smile can sometimes be used to patronize. Generally speaking, they're not good.

Anybody have any thoughts on this?