Girl's Behavior

What does it mean when a woman looks at you and their eyes light up?

I opened at set of doors and as I opened a woman was on the other side coming through as I was. Having opened it and she saw me, her eyes lit up. They kind of reacted.

Another time I saw the same woman, when leaving. I was on inside the building and she was on the outside with glass windows between us. As I saw her, I looked at her and she looked at me. As soon as she looked at me, her eyes lit up and she instantly looked way.

What does it mean when a woman looks at you and their eyes light up?
Post Opinion