OK, maybe a little.
J., it is impossible to prove a negative. One cannot prove that something does not exist.
For example. Prove to me that no fruit exists which is shaped like Ronald Reagan's head. Prove that there are no aliens on Mars. You can show me evidence which may indicate that these are true, but it is not proof. Only an affirmative statement can be proven. And any proof you may have that God exists may meet the burden of proof for you, but will not even remotely satisfy the burden of proof that others may have. Unless you have verified photographic evidence?
Atheists, or non-theists, at least the cerebral ones, base their beliefs on a multitude of well thought out and logical arguments. Perhaps the reason some atheists feel they have to tell the world is because of the same reason that many religions prosletyze their own beliefs - they feel that they can make the world a better place by doing so. Or in the case of some (many?) religions, they can make more money or obtain more power by doing so.
(Disclaimer) I make these statements for the sake of discussion, without regard to any personal beliefs. Any personal attacks and I'm gone.