"It depends on the context it's used, but for the most part I think the person that says it means well. I generally say "thank you" and go about my business. If I'm in a bad mood and I hear it, I might give a response of "And…"
Welcome to Atheist Nexus with its thousands of good friends.
Join groups when you can, like the busy discussion group “ORIGINS” (Origins: Universe, Life, Humans, Evolution, Religion..... ) with its 120 discussions and numerous video films.
One discussion (over 65 posts) is called "Proud to be Atheist". There's much to be proud about because atheists and humanists hold the intellectual high ground and recognise the folly of superstitious god believers for the pathetic nonsense that belief in the supernatural is.