ACHOO!

There's being an atheist, then there's being an ass.

My roommate does the same thing. He's very anti anything religious being thrown his way, even if its a common cultural thing thats just adapted into our society. Hell, he gets all bent out of shape when an employee of a store says Merry Christmas to him. I'm agnostic, tend to not like organized religion (or religion as a whole), but I'll still give courtesy of saying 'thanks' when someone says 'bless you'. This isn't acknowledging their religion, but showing gratitude that they're thinking of your well being regardless of how its expressed.

On top of that, this is in relation to a customer. Anytime you're handling customer service, you should not be ignoring a customer over something as petty as 'bless you'. If they started preaching, you can excuse yourself with a "I'm sorry, I don't feel comfortable discussing this" or whatever. But a simple 'bless you' from a customer shouldn't be ignored. Customer service is key, especially right now.

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