Pretend they're being nice. I'm serious. Just treat them as though they are being nice. Ignore their tone. They are looking for a reaction. Don't give it. That shuts down 99% of rude customers.

Malicious compliance. Follow every rule, every standard, every procedure exactly as you should. Always offer to remake whatever it is, and if they still give you trouble, tell them that you’re going to get your supervisor.

As I tell my new partners, you don’t get paid enough to deal with that, and it’s not in your job description. That’s why you have SSVs and SMs. Let them handle irate customers and nasty people, you just focus on staying in position.

TBH, treat them like they’re an unruly toddler. “Oh, you’re really in your feelings right now, why don’t you take some deep breaths and let’s see what we can do to help you get better control of your emotions”. Or, “Did you you get everything out? What outcome are you hoping for with that outburst?” Or, “Do you think that I allow everyone to speak to me like that, or do you expect me to make an exception for you?” Or, “I don’t continue conversations with people who speak to me like that.” The last one is kinda key, because when you say, “Don’t speak to me like that” it’s a request that they can disagree with. When you say the other thing, it’s a statement and you are deciding to not participate further in the exchange.

I pretend they are toddlers having a tantrum. It's just coffee, no one is going to die if it takes a bit longer, they are just being dramatic to get a reaction out of you. Don't give it.