I think I'll butt in here, please don't mind me.
I really think that you can tell a lot from a person from the look in their eyes, and the way they look at you.
How many people have gotten that intense felling when they look into the eyes of another person that feels the same way? How many people have looked into the eyes of another and just seen, true disinterest??
I think after a certain period of time you can really learn a lot from they way your significant other looks at you, and uses their eyes (even in a perfectly public situation).
I'm not sure who said it but I definately believe "The eyes are the window to the soul".
Pebcak