Socrates said, "True wisdom is knowing you don't know" to which I would add accepting our ignorance is how we really come to know anything. Ironically, our ignorance appears to be the source of whatever creativity, free will, humor, knowledge, and authenticity we might possess, but only to the degree we are both aware and accepting of our ignorance. As far as Socrates was concerned this was just a simple fact of life. If you are neither aware nor accepting of the fact that you don't know how to swim, for example, you'll have limited wisdom and humor when it comes to water. This "ignorant wisdom", or love, humor, knowledge, and sagacity acquired by becoming more aware and accepting of our ignorance, is what I like to think of as the foolish heart of agnosticism. The ability to once again, foolishly laugh at ourselves like a child as if we didn't have a care in the world, and find humble contentment in our ignorance, somehow knowing without knowing how we know, wonder remains the beginning of all wisdom.
For me, agnosticism is not a belief system, it is having the humble faith and personal integrity to accept your own ignorance as the only way to make any knowledge more meaningful, as well as, the recognition that you don't know if there is a God or not.