Why Customer Service Is A Two Way Street

Recently on my commute from work, I decided to stop at a coffee chain in Arlington, MA.
I had consumed a lot of water, so in reality, I needed to use the facilities, and I was craving a pick-me-up beverage and treat for the ride home.
As I walked into the shop, I noticed the barista behind the counter, and man in front of me had wrapped up his order.
I walked up and said “Hi.”
She nods but didn’t acknowledge me with a “Welcome, how are you?”
I look on the board to figure out what I’d like to order.