So I'm not sure about other parts of the world, but here in the US, the tradition is to say "God bless you" (sometimes shortened to just "bless you") when someone else sneezes near you. It's generally considered rude not to say anything. So I usually stick to "bless you" just to be polite and leave the religious connotation out of it, but even that seems weird to me.
What do the rest of you say?
What do the rest of you say?
That's MISTER Godless Vegetarian Tree Hugging Hippie Liberal to you.