Guilt Revisited

Long ago here, I wrote that "guilt" is considered negative and not Jewish and I wondered about how that fits with the idea of charata (remorse), a component of the teshuva process.

Once again, this time in R' Yaakov Bender's book on chinuch, it's down with guilt and up with regret. He says "there is nothing wrong with busha (shame) and regret," for this is part of teshuva.  He says, "This allows us to move on and to become great individuals without an iota of guilt. Guilt is what you want to avoid.  We don't want guilt.  We don't want negativity."

More from R' Bender: "Are regret, remorse, and embarrassment necessary? Yes, of course, with the proper teshuva.  Guilt? Absolutely not."

Maybe someone can explain to me the difference between regret and guilt, since the dictionary says they are synonyms.