I have run retail operations for over 25 years and have the utmost respect for retail clerks doing their job. Generally speaking they are low paid employees that take more than their fair share of abuse from customers for things that are either out of their control or unreasonable. I suspect many of the worst customers have never had to work a retail job, for if they did they would gain a whole new understanding for what they go thru on a daily basis for a very small wage.
John