Why share some things?

I am always amazed at what people, total strangers, feel comfortable sharing with me.  While standing in line at Walmart, I saw lady get behind me with 2 items, I had about 10.  I suggested she move ahead of me.  She was thankful and then for some reason started talking to me.  As she was checking out she said she wasn't born in 1947 and asked me and I shared no, I was born in 1969.  It was downhill from the moment on.  She told me she had a daughter that was my age and had passed away.  I offer my condolences and she stated it was a freak accident over 20 years ago.  Then she stated she has a daughter in treatment for cancer right now and her Mother passed away last year.  At this point, the woman had completely checked out and paid and the cashier was ringing my items and I was ready to pay.  The grieving woman told me that people try to make her feel better by saying her loved ones are in a better place, but she doesn't feel good with that information as she wants them here with her.  I am trying my best to think of how to handle this in the most respectful way when suddenly the grieving woman looks at her watch and says, well, I am in a big hurry, gotta go.  The cashier and I just looked at each other and shook our heads.