Guilt is useful when used wisely and with care, Tangney observed, "but the question is, how do you want people to feel bad, and how badly do you want them to feel?"

Parents -- and all family members, for that matter -- should resist the urge to lay it on thick or to give their children the message that they are a bad person because of something they've done.

Instead, she says, call attention to specific actions, point out the consequences of these actions and focus on feelings of empathy for people who have been adversely affected. Spend time on the constructive: How can you develop a plan for fixing the situation or making amends?

But what if the guilt trip isn't justified -- say, if you must work the day after Christmas or risk the wrath of your cranky boss?

"Then don't feel guilty!" Tangney advised. "Reason yourself out of feeling guilty. There are enough things we have to feel guilty about for real, things we really did wrong. That's what guilt is for. Not so we can feel guilty about things that really aren't our fault."

The shame-prone

Why are some people adaptive in their guilt while others feel shame in response?

"We don't quite know, but we do know that shame and guilt exert a profound influence on people from early childhood all the way into adulthood," noted Tangney, who is currently examining the implications of moral emotions and cognition in longitudinal studies involving the rehabilitation of criminal offenders.

If you are inclined to feel shame, Tangney offers this advice: "What I found in my clinical work or teaching students is that sometimes, just educating people about the difference between shame and guilt, and the practice of recognizing when they feel shame, can make a huge difference. If you are feeling shame, do a rational rechecking and focus on a plan to make things right."

What we know, says Tangney, is that there are good ways and bad ways to feel bad. And assuming it's justified and you have done something to feel bad about, then that guilt you are feeling may be perfectly OK.