In this day and age, and I'm generalising,... you only receive friendly customer service from someone who is running their own business. i.e, they care enough to make sure you come back again!
If you pay teenagers the minimum wage to work in a faceless organisation with few prospects, then (generally) you get poor service.
Now, I'm not saying that is the right way to be, I'm just saying that its human nature, or it SEEMS to be these days.
I've seen it, even within my own family.
I remember starting out in the world of work, and it was important to make a good impression to make sure you could be in the best position for any career progression.
But, (in general, with a few notable exceptions) you just don't see that attitude so much these days.