I believe I have found what atheists, theists, and any other 'ists' seem to have in common.
None of us very much like our beliefs/thoughts/ideas/convictions questioned, and we don't mind telling the offender so.
I wonder if there is really such a thing as "agree to disagree".
I doubt we could agree there is such.
Just a tid-bit to think about.
update: Hmmm... What about an agnostic? I have never spoken to one that I know of. Would they hold this common that us 'ists' do?