Remember the last time a client, a boss or a co-worker gave you a hand-written thank-you note to tell you you’re doing a good job? Maybe someone at work has surprised you with flowers, an unexpected gift or a bonus. Has a vendor ever slipped you a gift card worth the price of a cup of fancy coffee, just to show appreciation for your loyalty?

It felt good. It might even have prompted you to keep up the good work. You might have thought back to that gesture when you toyed with moving to a different company or switching to a cheaper vendor.

Your gesture of appreciation doesn’t have to be a gift. Simply saying “thank you” can go a long way toward improving employee morale, retaining valuable staff members and keeping your clients coming back. In fact, in survey after survey, more than 20 percent of employees have said:

  • If they don’t feel recognized for doing good work, they have recently applied for a different job—compared with 12 percent of employees who do feel recognized.
  • More appreciation from bosses would make them happier at work.
  • They prefer written or oral “thank yous” over extra time off or gifts.

Saying “thank you” is a simple but powerful gesture. And it can lay the foundation for a positive relationship with bosses, subordinates and co-workers when the time comes for you to ask someone to go the extra mile.

Showing appreciation builds goodwill. People appreciate being appreciated. Someone who feels appreciation from you is more likely to return the gesture by agreeing to your requests. They want to let you know that they appreciate you, too.

Professional salespeople—at least the good ones—know this. They keep in touch with their customers long after they have made the sale. They thank them for their business. They check later to ask if the customers are happy with their major purchases. They ask what else the customer might need that they can offer.

It’s all part of creating a “customer for life,” and it’s a strategy that any employee, manager or vendor can imitate in an effort to create good working relationships and agreeable clients, staff and co-workers.

Consider the late Bob Bergland, a former U.S. Secretary of Agriculture and member of Congress who later worked as the general manager of an association with hundreds of employees. He was known for making the effort to learn the names of as many of those employees as he could, and for taking the time to stroll around the building every now and then to shake their hands and thank them for their service—by name.

When it came time for him to ask employees to go the extra mile, they were happy to return that goodwill.

I can share a practice of my own that works for me: As a small business owner, I hand-write thank-you notes on fancy paper and mail them in time for Thanksgiving delivery each year to every client, employee and vendor I have ever done business with—even former ones.

When I find myself in need of a favor, a discount or a rush job, they’re happy to help me.

Especially if someone gives you something you really want, like a raise, a promotion, a job or new business, it’s important to show your gratitude. In fact, most hiring managers say they expect a thank-you email from every job applicant who got an interview.

Even if you didn’t get the raise or job you asked for, show your gratitude to the person who spent time and consideration on your request. And don’t show that gratitude just once. Continue to follow up with everyone who has helped you or considered it.

That kind of follow-up not only sets you up for positive results with this person in the future, but it signals that the professional relationship you want reaches far beyond a single transaction. It says you care enough to stay in touch.

You don’t have to spend a ton or money or time saying “thank you.” Simple gestures can be just as powerful as grand ones. For example:

  • A note—handwritten or via email—that includes a specific reference to something the recipient did for you or talked to you about can elevate a casual business relationship to a more important one.
  • After crashing on a deadline, an in-person pat on the back for a job well done—again, with specific mentions of achievements—lets an employee know that you notice and appreciate hard work.
  • Posting a positive online review for a company or a service professional takes just minutes. But its impact can be enormous if it results in additional business for the vendor.
  • Returning a favor after someone has done one for you tells the other person that the relationship is not one-sided.
  • Some sincere words of appreciation can pick up an employee or coworker who is showing signs of burnout or depression.
  • A gift card worth as little as $5 is still a gift. Hand them out to people who serve you year-round, like the person who delivers packages to your office, the agent at the rental-car company you frequent or the receptionist in the lobby of your building. Don’t wait for the holidays; make it a surprise.

When you say “thank you” to someone who said “yes” to a request, you pave the way for the next “yes.” Follow the lead of the most successful sales professionals whenever someone gives you something or does something for you: Realize that hearing a “yes” isn’t the end the deal. It’s the start of the next one.