Business is busier than ever, and it's easy to forget to take time to tell your employees just how grateful you are that they're working for you. This is a mistake. Showing your gratitude to employees is one of the simplest and most powerful things you can do to create a productive workplace filled with happy, engaged people. And that's something every business could use more of.

Believe it or not, 58 percent of employees report that they seldom if ever get a thank you from their boss. The good news is that there are many ways to show your gratitude, most of which don't require spending any money at all. Here are 11 highly effective ways that you can show your gratitude to your employees quickly and easily.

1. A dose of autonomy

Give your people some autonomy and watch them grow! Reward your employees with a flexible schedule to show that you trust them. Let them choose to enjoy their cup of coffee a while longer in the morning as they work from home. Or perhaps one of your employees is a night owl and would appreciate a few of their working hours to be spent during the evening at home.

2. Treat your employees to lunch

Yes! Bringing in lunch for your employees has an amazing effect on mood and overall happiness in the workplace. Or take that one special employee or team out for lunch to show that you really are seeing and appreciating their amazing contributions.

3. Special recognition

If you have a company newsletter, be sure to recognize standout employees or teams. If not, make sure to name them personally during meetings or get-togethers and recognize their efforts.

4. Show and tell

Create a special board in the office--a chalkboard wall, fancy glassed-in display, or corkboard--where your employees can show what is important to them or new in their lives. A new baby, an upcoming marathon, and a special event they are participating in--whatever the case, this is their place to brag a little or get support.

5. Be respectful

Even if you're having a bad day, never show your anger! No matter how many times you praise an employee for a job well done, one lash out of anger can negate it all. Always put on a smile and be respectful at all times.

6. Let them take a half-day

If you've got an employee who went of his or her way to go the extra mile for a customer or on a work project, tell them to choose a day they would like to come in late or leave early.

7. Keep up with their non-work accomplishments

Publicly acknowledge when your employees accomplish something notable outside of the office. Whether it's, say, adopting a child, or having their spouse open a new restaurant in town, employees feel appreciated and seen if the boss actually knows and cares about what they're up to outside of work.

8. Make your confessions when needed

If you make a mistake, fess up right away. Don't be afraid to say you're sorry--your employees will appreciate and respect you more when you do.

9. Casual days are back

There is something very special about putting on your jeans, t-shirt, and sneakers and heading to the office. Have a casual dress day once a week or month--an amazing mood lifter!

10. Field trips

So your team closed the deal and you're ecstatic! Take them on a field trip--go fishing, to the zoo, to the movies, to a customer site--do something fun outside of the office to show how much you appreciate them.

11. Show you care

If someone has a sick child or spouse at home, suggest some time off to care for their loved one. If an employee has a Girl Scout selling cookies, purchase a case and then share them with the entire office.