IF NOTHING is Prohibited, so WHY does Everyone Feel Gulity?

For the history of mankind, everyone has hoped that they could make their OWN rules, and live by those.  Then, of course, when we try to do just that we find our own rules a bit too confining, so we loosen those. But, regardless of our ability to Rationalize most any behavior, we still MUST deal, inexplicably, with...guilt! Odd that. We feel guilty about: Our carbon footprint, Our failure to eliminate Racism, Our failure to elect the right person to some office or the other, US military interventions, US military non-interventions, Our failureS as parents, children, neighbors, spouses, etc. A few years ago there was a popular female Christian singer, Julie Miller, who recorded a popular song titled, "My Psychiatrist".  The words in the song went something like this, "They said when I felt guilty, my mother was the cause, Now I know the reason is, only that I was." That's pretty clear, pretty honest, and pretty useful. And, surprisingly our abandonment of religion, particularly Christianity, has done little to assuage our guilt.  We are vaguely aware, even as ardent atheists, that we DO indeed bear guilt and we do INDEED need to be FORGIVEN. In Julie Miller's song, she talks about her NEW psychiatrist, Jesus the Christ.  She speaks of his "experience" and his low (free) fees. Maybe Ms. Miller was onto something.