For some, they are the two hardest words to say. But learning how to make a sincere apology is not only a necessary skill, it's an art.

Just look at the headlines. Singer Kelly Clarkson lashed out at record mogul and star-maker Clive Davis after they clashed over the content of her new album. But last month Clarkson released a statement on her Web site taking back her words. "I'm well aware that Clive is one of the great record men of all time," Clarkson said. "I really regret how this has turned out and I apologize to those whom I have done disservice."

Sounds sincere. But is it? Celebrities are told when and how to apologize, usually when their careers are on the line. Meanwhile, politicians are masters of the unapology, showing remorse largely because they got caught and often without uttering those two magic words. Even for regular folks, the state of saying "sorry" is a sorrowful one. Why is it so hard to show contrition?

"We tend to not apologize because we think it's a sign of weakness and vulnerability," said Sheila Quinn Simpson, the Michigan-based author of "Apology: The Importance and Power of Saying 'I'm Sorry' " (Balcony, $12.95). "We tend to not take responsibility for our actions. It's always somebody else's fault, and if they apologize first, maybe you will, too."

We are also a highly litigious society, Simpson explained, so to not own our behavior is often recommended, at least legally.

In other words, yes, you caused the accident. But don't apologize, or you'll be culpable.

Ironically, Simpson pointed out, we are obsessed with the importance of forgiveness, but nobody talks about the other side of it, which is apology. There are no apology cards in the greeting card aisle, and we rarely acknowledge how powerful and healing an apology is — for the apologizer.

"Apologizing means acting with integrity and being aware of how our behavior affects people for the good or the bad," Simpson said. "It is our choice to avoid or to face the music."

As a rule, Lindsay Newsom tries to avoid conflict. The Contra Costa, Calif., resident describes herself as a moderate person who always sees both sides. But if she does hurt someone, she's the first to offer up an apology. "I want the situation to be as normal as possible as soon as possible," she said.

Recently, Newsom took the side of one of two friends involved in a conflict. Upon reflection, she realized she'd taken the wrong side.

"I went back to the other friend and said 'I'm sorry, I handled it wrong, and it was the wrong side to take,' " she explained. The friend accepted.

Sarah Gorback of San Francisco is a fan of the silent apology, especially when it comes to petty arguments. Think back to the times you exchanged hurtful words with mom, only to show up half an hour later, helping to wash dishes at her side.

"A verbal apology can mean so much less anyway," Gorback said. "Besides, without saying the words, you can maintain a bit of pride and still passively admit you were wrong."

Action apologies are acceptable, Simpson said. But in general, a verbal or written apology is most effective. They convey emotion and remorse best.

Timing is paramount. "Do it as soon as you have that gut feeling," Simpson said. "That minimizes the rage, resentments or judgments that can escalate a situation. It's not time that heals, it's what you do with the time."

That said, it's never too late for an apology. Wes Allnutt learned that when he apologized to his parents for a lie he had told 16 years earlier.

"I felt no longer tied down by it," Allnutt said. "When you admit you're wrong, you clean up your past and sleep better at night. I walk with my head held a little higher."

Even the phrasing and delivery of an apology can be transformative. Avoid the word "but," as in "I'm sorry you feel that way, but. ..." Simpson said. Instead, try "I'm sorry I wasn't more careful with my words."

And if you think a proper apology rides only on the person giving it, you're mistaken.

"A person can be poor at accepting apologies, for example, teasing or making more of the offense all over again when the apology was meant to put it to rest," said Nancy Perry, a clinical psychologist and clinical director of Concord's Center for Adaptive Learning.