We've worked in the same building for a few years (different employers) but only small-talked on rare occasions until lately.

If I recall correctly, she mentioned taking in a kitten that had wandered into the lobby of our tiny building. I explained that I had let him in, and out of the cold, before that. She suggested drink and we eventually hit the bar and it escalated from there.

Moral of the story: help save every lost kitten that you find.