Wow, I felt so sorry for the Chick-Fil-A worker. She was so pleasant (like most of them are) and was eager to give him his free water and he had to be a complete ass. She has nothing to be ashamed about and shame on him for taking out his dysfunction on an innocent human.
She valued her employment and employer a lot more than mister bigshot. All work, even what many might consider humble, has value and dignity.