shame

I remember hearing at a retreat once a talk about shame. "Shame," we were told, "is the most utterly useless emotion. And the most destructive."
I walk the line each day knowing that it is only our loving God who can truly forgive and love us unconditionally. And I try to believe that I am loved, I am forgiven. But few things in my life really exemplify that. I guess that is the ultimate point of the plea: forgive us our trespasses as we forgive those who trespass against us.
If I'm going to purgatory, I'm fairly certain that what I'll be punished for (or cleansed of?) is the long list of the things that I refuse to forgive about myself. The things that I am ashamed of. But we don't really wait for purgatory, do we. We punish each other and we punish ourselves everyday. We build walls, carry resentments, lash out...the list is long of our human failings.
How can we accept love in the weight of such overwhelming odds? How can we extend forgiveness, particularly to ourselves, when our culture does not embrace forgiveness? I can hear them chanting in my head now, "crucify him, crucify him."
Sorry if this is kind of rambling. Just my state of mind today.