My current guru, Brené Brown, the "shame researcher," explains the difference between shame and guilt.
Shame is: "I am a horrible person."
Guilt is: "I did a horrible thing."
See the difference?
Guilt is an effective means for improvement, as opposed to shame. Instead of flagellating oneself after a goof-up that one is pathetic, disgusting, etc. etc., one can calmly accept one can do better, and march forward, instead of looking back.
This very much applies with parenting; it has been verboten for some time now to refer to a child as "bad" for this reason. Focusing instead on unacceptable behavior—"You were very naughty"—can show results, while the previous merely reinforces despair and fatalism.
When I first came across the difference between shame and guilt (my copy of I Thought It Was Just Me was lent out and I can't type up specific passages), I was struck by the pattern in our Yomim Noraim liturgy.
"Ashamnu, bagadnu, gazalnu, dibarnu dofi—we have sinned, we have betrayed, we have robbed, we have spoken slander." We don't say, "We are sinners, we are betrayers, we are robbers, we are speakers of slander."
If I say that I am a sinner, then there is no hope for me; I am what I am, as much as I am Jewish and female. But if I confess my sins, acknowledging them as actions in the past, admitting my culpability, then I can become someone better.
Best Hungarian saying, which I will say yet again: You look back, "you turn to salt." Sólet.