If someone in customer service replied with hurried, rushed, two word responses I would consider them rude and possibly report them to the manager. Your job as someone who works with the public is to give them the explanation they deserve as a customer. If I went to your place of work and you just kept yelling "DIET COKE" while I'm saying "COKE" I would either think you were rude or slow. And then I'd report you. It's not that hard to say we're out of regular coke. And to wait to be prompted to explain something is rude and yes, it makes you bad at your job.

He shook his head and said "No, that's not what you want" when she said coke twice.

Nobody until 110 even brought up the fact Splenda or no Splenda diet has aspartame which is terible for you and is actually worse than straight up soda almost every diet soda has aspartame and kind of pop is bad for you diet just happens to have worse for you ingredients even if it is healthier in some areas even powdered water flavor packets have aspartame just FYI and many people even have a allergic reaction to aspartame

Damn that's harsh.

What a jerk. I hope you didn't tip him.

I hope you complained to his manager and didn't leave a tip. That's completely inappropriate behavior.

Diet coke? No tip

Order him a complaint to the manager.

waiters work for tips so I'm a bit doubtful this happend

Maybe they were out of regular coke and you had to get diet?