Q: Why do some people, even children, regardless of religion, have a clearer concept of God, Jesus' teaching and religion than others?
A: I think it is interesting that you mention children as having a clearer concept of God. I have found that to be true as well. I've always thought that it could have something to do with the fact that they have more recently been with him, and have not yet "learned" to forget about him. Sometimes, as we grow up, we get so involved with life and all the distractions of life that we lose sight of our need for God, for Jesus, for religion....
Jesus loved children, and he was always fond of saying that we had to become as little children to really enter the Kingdom. Children are naturally trusting, naturally optimistic, and naturally hopeful, until they are taught otherwise. And so, it is these kinds of qualities that help a person gain a clearer concept of God.
Those who are less trusting, and more pessimistic will not make as much progress because they lack the child-like attributes. Remember, it is that parent/child relationship with God that is so important, and so we have to learn how to become like a trusting child again to really know God as he wants to be known—as our loving Spirit Father. Some people understand this—some do not.
Also, there is the matter of desire. A person who sincerely desires to know God will naturally find more of him in their personal experience. Those who see no need for God—those who are satisfied and happy with themselves—will naturally not take the trouble to really look for him. But anyone who sincerely seeks God WILL find him. This is true of any kind of religious pursuit, whether it is God, Jesus or religion in general. It is always a case of "seek, and ye shall find..." And the opposite of that is "if you don't seek, you won't find..." It seems to me that is usually the sincere seekers that have the best experiences of God.
Thanks for this question. I hope my answer has been helpful to you.