A friend--a normally very cynical friend--received a thank you note from Beth Stern he can't stop talking about.

First some background: When they were still dating in 2002 Howard Stern and his wife Beth got their English bulldog Bianca.

Howard is a radio personality, America's Got Talent judge, and the king of all media. Beth is a model, TV personality, author of the bestselling guide to choosing and caring for canines Oh My Dog, and an extremely active spokesperson for the North Shore Animal League, the world's largest no-kill animal rescue and adoption agency.

Let's just say that if this was a trial, all parties would immediately stipulate her credentials as an animal lover and activist.

Sadly, Bianca the bulldog died in July. North Shore set up an In Memoriam page to mark Bianca's passing and recognize her efforts as a spokes-dog and fundraising calendar model. Since the shelter is a non-profit charity that relies on donations to fund its operations, the page also includes a link visitors can use to make a donation in Bianca's honor.

According to North Shore, hundreds of people have done so.

My friend is one of them. He gave a contribution, felt good about it, and--as we often do when we make charitable donations, however heartfelt--he forgot about it.

Until he received a card in the mail.

On the cover of the card was a photo of Bianca. Inside was a handwritten note from Beth. Her thank you wasn't canned or formulaic; she was obviously touched by his expression of sympathy and donation and took the time to reach out in a personal and individual way.

"I still can't believe it," he says. "I've donated to plenty of causes. I'm not looking for recognition, even though I appreciate when an organization sends a thank you card. But for her to take the time to handwrite a note to someone she doesn't even know and will never meet... that just blows me away."

It was a simple gesture, one he and hundreds of other people will never forget, since Beth personally thanks everyone who makes a donation in Bianca's honor.

It's also a simple gesture that provides a great business lesson.

Say you land a new customer. Appreciation is the one thing that should never be scaled or automated. If you're truly grateful (and you should be!) why not take the time to personally express your gratitude in a heartfelt, genuine way?

You'll be memorable, if only because so few people do. And you'll spark a real connection and take a huge step towards building a lasting business relationship.

A sincere thank you isn't just good manners--even though good manners is reason enough.

It's also good business.