Interacting with a Cashier

I just got off the phone with one of my BFF's, let's call her Lacey.  I hadn't spoken to her in quite some time so I was missing her counsel and company.  One of the reasons why I seek her counsel and company is because she is so very refined.  While we were chatting on the phone, I was in the comfort of my own home and she was online at the pharmacy.  She told me she had to get off the phone and call me back since she was about to pay for her purchase.  I admire that a lot.  I cannot stand to see people chatting on the phone, loading their reusable shopping bag and trying to pay for their purchase at the same time with an in the flesh till operator.  What's that person supposed to do?  Their job is hard enough, ringing up yur purchase of US Weekly, a snicker's bar and and anit-bacterial ointment without you pretending like they're just some payment machine. 

Now let's see if Lacey calls me back!

Quite frankly, I like to avoid human interaction as much as the next misanthrope but if in front of me, I will pay the respect that is due to a person that provides me a service and that means I say hello, thank you and good bye.  Acknowledge that they are a person.  They'll appreciate it.  Trust me.