What to Say When You're Shopping?

I was shopping with my nephew, Dexter in Ayala Shopping Center few days ago when I realized the most important thing to do when shopping. The mall was huge and I was so amazed with the additional terraces or designs. The mall looks so beautiful at night and there were only few people shopping. Standing outide Starbucks coffee, I took time to enjoy the view and the bright colors. My nephew also enjoyed and he just wanted me to take photos of him near the water fountain. I just decided to go inside and picked some grocery items when the mall was about to close. So we had to be quick. We only got 15 or 20 minutes before Metro Ayala would close. My nephew wanted to push the cart so I picked things as fast as I could. While we were at the counter there were only few people since some counters were already closed. I heard the cashier and her assistant (bagger boy) talking that I would be their last customer then they would be home and be with their kids. I looked at them. They looked young. I thought they were still single.
The cashier asked, "How many did you get today?"
The bagger replied, " Oh I got a lot..too many people are kind today so I don't feel too tired."
I couldn't guess what they were talking about. I was thinking it was not a tip since giving a tip in shopping malls is never practice here in the Philippines, as far as I know. Then the cashier asked me if I would use cash or credit card. I said, cash.
After the bagger packed the goods, he smiled and handed the bags so I said, "Thank You". Then the cashier said, "wow you still got one before we go." I realized that those two were counting the times when customers would say, "Thank You". It's not too hard to say these words, and we didn't know