My first reaction to customer service in Grenada was frustration that it was necessary to go in person to pay bills. I was so used to paying all my bills in Canada online. Things have progressed, but you are required to have a Grenadian bank account, which I don't as yet.
Maybe that's why some folks aren't too friendly. All the long line ups stress out the workers!
On the other hand, once someone gets to know you, they might just go to the ends of the earth to help you. Pretty soon you'll be trading food or romance novels.
I find most Grenadians very friendly, but if I can generalize, I would say that most office workers (especially government) are too serious for me. I don't know if they are trained that way, but it seems unnatural compared to the friendliness of other business folks in different areas.
I have found that is a good idea to inquire about returns before purchase. Quite a few shops only offer exchange or no return at all.
I hope this is the kind of feedback you were looking for.