This holiday season I did something I rarely do: I clicked through an Instagram ad. By doing so, I discovered Artifact Uprising, a company that prints custom photo books, cards, calendars, and more. I was taken by their clean designs, by their story, and by their focus on sourcing eco-conscious materials—like their “Wood Calendar”—a perfect gift for the grandparents.

The calendars arrived, and they were great, but there was something else that made Artifact Uprising’s product delivery stand out. Included with the shipment was a simple thank you note.

Fresh off the post-holiday rush of online shopping and shipping, stop and consider: How many brands included a thank you along with your packing slip and return labels? Which ones were they? Chances are, you remember them.

Top of heart, top of mind

Even in business, a thank you note reinforces the personal relationship behind an interaction. A box that arrives solo is merely an exchange of product for money. There’s nothing wrong with that, except that it becomes easy to forget that this is a transaction between people making a choice to do business together. Were it an in-person interaction, the lack of a “thank you” would be very apparent.

Personally, the inclusion of a business thank you note is something I always notice. Brands like Joybird send a personal thank you with each shipment, signed by every person who’s had a hand in creating your piece of furniture. My first order from Modern Citizen came with a handwritten thank you from the founder, as did an order from the children’s fashion label neve/hawk. A colleague recently received personalized gratitude from an employee at Tumi. I even have one thank you, scrawled on the back of a beautiful postcard, taped above my desk. It’s from an artist on Etsy, whose work I’m now constantly reminded of.

For me, the thank you usually creates a brief, but tangible moment where I’m holding the physical note in my hand as I read. I generally stop and think, “How nice,” before sending it the way of the recycling bin. It may seem wasteful for so fleeting a moment, but it’s worth asking: Can a simple text or email get the same job done? And how much does it impact my decision to do business with that person or company again?

Reciprocity is good for business

Sending a thank you note is more than a rote act of politesse and etiquette. It’s an expression of gratitude, and including—increased optimism and reduced stress, and better physical and psychological health. Gratitude helps build and maintain better relationships, too. Thank you notes serve to re-emphasize personal bonds. Even just a few kind words of support tells your recipient that you recognize their effort, or that you, in effect, see them.

Sending a thank you note is more than a rote act of politesse and etiquette. It’s an expression of gratitude, and gratitude is linked to all sorts of great stuff.

The business thank you, in particular, is something the modern maker community and smaller, newer e-commerce retailers do well. You might say they have more time, lower volume, or that they need buyer loyalty more than their bigger fish competitors. It can also be argued the other way—that these folks have fewer hands and less time, and still they make the effort. One might ask whether the companies who make the effort are helping to bring gratitude back.

Consciously or not, businesses who send thank you notes recognize that gratitude inspires reciprocity. This idea that one kind act inspires another, or that generosity of time and spirit can actually help one get ahead, has been proven scientifically. In fact, studies reported in The Role of Customer Gratitude in Relationship Marketing, revealed that investments in customer gratitude, or gratitude-based reciprocal behaviors, led to increased customer trust and commitment—and ultimately to longer-term, quantifiable benefits.

You used to text me on your cell phone

Margaret Sheperd, in The Art of the Handwritten Note, makes a particular case for the handwritten note. If the most important thing is to express gratitude, there are, of course, many ways to do so. An email or text message is immediate. It wastes no paper and also creates a moment of pause.

In contrast to a phone call or text message, a handwritten note, Sheperd says, “doesn’t arrive demanding to be read when you’ve just sat down to dinner.” It won’t get lost in the sea of other texts or emails that are formatted in the same way. In her book she taps into the romanticism and physicality of a note, showing that it is more beautiful and more personal than an email or text. It is also technology-agnostic.

That aside, Sheperd states plainly, “Adapting to the needs of every fresh generation, [the handwritten note] continues to connect people. In fact, the handwritten note is even more vital now than it was a few years ago because it’s less routinely used.” Today, when a handwritten note arrives in the mail, you pay attention. She writes, “It announces beyond a doubt that the reader really matters to you.”

Thank you notes turn up the heat

Sheperd’s probably right. One thank you note I received this season was from a business partner I’d exchanged a handful of emails with and met only once. She wrote me—in her own hand—a personal note, which now keeps proud company with holiday cards from family and friends. Maybe it’s because so few people send handwritten thank you’s that hers stands out. Arguably her note adds another line to the story of our specific relationship,

Her note adds another line to the story of our specific relationship, creating an emotional connection more memorable than a soon-to-be-eaten (and forgotten) fruit basket.

And while the thank you note from Artifact Uprising wasn’t handwritten, it still felt sincere. It didn’t include a coupon, or a lure for more business. Certainly a handwritten note would have been more personal, but as a new customer, I found the simplicity of the company’s note appealing.

There are always a variety of factors at play when customers are making a purchase decision, but these anecdotes reveal something tangible. Thank you notes can make a difference in the way your customers feel about your business. And, in a word, your customers will probably feel: warmer.

Suzanne Barnecut is a content marketer for Zendesk and a frequent contributor to Relate. She is fascinated by technology, but a diehard reader of paper-made books and sender of snail mail. Find her on Twitter: @elisesuz.