I could not be an Atheist because I've had too many coincidences and experiences where everything else failed, but prayer filled my heart with peace, joy, hope, and consoling visions, but I sympathize with Atheists.
If God left a clear message in the sky every now and then or spoke clear messages to people, how many Atheists would there be? Would you still be one?
God doesn't do that and obviously He knows that the result is that there will be disbelief. God wants it that way, therefore it must be a good thing (in His opinion.)