I'd like to give a quick update. Ever since I've made a concerted effort to show my empathy I feel like I've gotten much better feedback. I've also begun to use little hints of inflection in my voice when greeting customers, and have even been bold enough to try to strike up a quick 1-2 minute conversation with almost each customer.
I do have one question though. Since each customer is only there for about 2-3 minutes (as long as no complications arise), I feel stupid trying to start a conversation when I know they'll be leaving very abruptly. How do I mitigate this feeling? Is this where the term "small talk" is actually literal?