I had to register a death last week. An uncommon event for me, but a run of the mill occurrence for the public servants providing the service. So you'd think that the anxiety level of their "customers" would be second nature to them and that any potential glitches would be approached with that in mind.
On the other hand, they might choose to retreat to a default position of ensuring that they covered themselves and their job description regardless of the customer service deficiencies that encapsulates.
It's an extreme example I know, but it has parallels in every business. Ideally, you're making sales and meeting customer needs every day whereas your customers are making those purchases far less frequently. Repetition may cause you to forget that fact. That's only natural.
But it's your job to remember each and every time how stressed your customer potentially is and how long-lasting an impression you can make by easing that stress. Or not.