Maybe you need to be less soothing and less of an audience for people who seem drama-queen prone. Feel free to get chillier and less welcoming as they get more hysterical.This is not likely to diffuse the situation.
Perhaps not, but I do think that being soothing can encourage the drama-prone.
I think the OP is perhaps overextending her role--and I think it would REALLY overextend her role to offer people tissues, glass of water, etc. Just say, "I'm sorry you're upset; please have a seat and give me a moment to think what I can do to help you. No, please sit down over there, I need to concentrate."
Or maybe even, "Is there a friend you can call, since you're upset and need someone to talk to? Perhaps that might help you."
I do agree that saying "calm down" isn't going to help. I once was having a dispute w/ a car-rental person when our reserved car seat wasn't available at the airport at midnight, and she just stood there, looking at us, as I held my sleeping two-year-old. I wasn't going to break the law by leaving the airport without one, and every suggestion I'd had, she completely countered with something non helpful ("the manager's gone home" "No other rental agency has one either"). So I got a little testy; not as bad as many people might be, but I was definitely upset.
She said, sort of snotty-scoldingly, "I'm not going to help you unless you calm down." I blew up--she should be helping me, period; it shouldn't be conditional. You're customer service, and your company screwed up, you fix it no matter how rude the customer is. And it wasn't "helping" me to get me the thing I reserved; you're not "helping" *me* by fixing your company's screw-up. And she hadn't seen "non calmed down" yet!!
Fortunately, I was smart enough to say one sentence and turn away (I gasped so loud after she said that, and said, "you won't help me -unless- I calm down?!"), and leave everything to my DH.
So yeah, if you want to say "calm down," you need to camouflage it quite a bit.
I like the, "I think it might be in your best interests if you can collect your emotions, and direct them into firmness and clarity" concept.