Real-life example: "At a dinner party, I ranted on and on about a local company's president who'd had an affair with his secretary," says a woman from Rhode Island. "Then I looked around, and no one was reacting. So I said to the man next to me, 'Now go ahead and tell me the secretary is your sister.' He said, 'No, it's my mother.'"

How to remove your foot: Don't try to explain yourself — you might only make things worse. Just apologize earnestly and say, "Please forgive me." If you're griping about someone who, as it happens, overhears you, you need to own up. "Blame it on yourself," says author Caroline Tiger. "Say, 'I'm sorry. I'm having a really bad day. I don't know what got into me.'" Peggy Post, the author of Emily Post's Etiquette ($38, www.amazon.com) says, "One of the greatest acts of kindness is to be a gracious forgiver. Hopefully the person will let you off the hook" — or at least not gripe about you.

In the future: "The standard advice would be to not gossip, but you're going to anyway — it's human nature," says communications coach Nick Morgan. "So just make damn sure that you know the person you're gossiping with" — and always be aware of who is within earshot.