What if you had an extra 40 hours a month? You get done everything that you need to do, and you still find yourself with the equivalent of an extra workweek’s worth of time left over. What would you do with that time? Usually, it’s going to be something like spend time with hobbies or read more or sleep more or reinvest it into the business.

There are three groups of people. The first group are the focus masters, who have never had any issue with time management, almost from birth. They have been organized; they have been on time.

The second group are the nomads. These are people who start as focus masters, but then something happened over the last five to 10 years, and they lost their way.

The third group are the chaos masters. The chaos masters have always struggled with time management and organization. They’ve learned how to be successful in spite of their natural tendency to create chaos and disorder wherever they go.

Basex Research, several years back, surveyed thousands of knowledge, or white-collar, workers around the United States and found that the average knowledge worker loses 28 percent of his or her day due to two things: interruptions and the recovery time associated with those interruptions.

I am going to use different words ― “switches” and “switching cost” ― but it’s the same thing. You are working on something, your attention switches, and then you have to go back to whatever it was you were working on. Remember that first question I asked: What would you do if you had an extra 40 hours per month? This is where that time comes from. And if you can reduce switches, you are going to recover that time.

I want to do a little exercise with you. Take a piece of paper, and then just draw three lines across it so that you have four rows. Mark Twain popularized the saying “There are three kinds of lies: lies, damned lies, and statistics.” I say, “There are lies, damned lies and multitasking.” Multitasking is worse than a lie because it’s a lie that we live every single day, and you are going to experience the consequences of that lie.

On that piece of paper you created, write in the first row the phrase “Multitasking is worse than a lie.” In the second row, write the numbers 1 through 27. Write down your approximate time when you’re done. I’ll call out the time every five seconds so you know where we are at. Get ready, get set, go.

We are going to simulate what you think is happening when you multitask. People think that they are doing multiple things at the same time. But what they are doing is switch tasking: switching rapidly back and forth. For instance, let’s say that you are trying to watch this presentation while you are answering an email. You are not actually doing both because your brain can’t handle multiple active tasks at the same time.

This time, on the third and fourth row, write, “Multitasking is worse than a lie” and 1 through 27. But this time, after every letter you write, write a number. For instance, write, “M” and then “1,” “U” and then “2,” “L” and then “3,” and so on. Get ready, get set, go.

You just experienced the first three costs of switch tasking. What’s the first most obvious cost? Well, if you look at the difference between the two times you did it, odds are you saw an increase in time. For some of you, it was 20 to 30 percent; for some of you, it was as much as 100 percent. Let me explain what happens to you when you lose time. You will be sitting at your desk, typing an email, focusing on a response, and then a message comes in on your phone, and someone asks you a question. You switch away and answer the question. Now you have to figure out where you were on the computer, restart, reread what you were doing and start again. Lots of lost time.

Or if you are a chaos master like me, you’ll send the answer, look at your desk, see a piece of paper, pick up that piece of paper, fill it out, see another piece of paper, pick that up, work on that for two hours, go to lunch, come back, and three hours later you still have an unfinished email on your screen. Whenever you switch tasks, the amount of time it takes to complete things increases.

The second cost is, take a look at the difference between the work you did the first time and the second time. Notice any differences? Notice things scrawled out and things scribbled? Words going up and words going down? How many of you ended up on a number other than 27? Whenever you delegate something to someone on your team, and you see them making silly mistakes, take a close look at whether or not they were switch tasking when you asked them to do it. Because when people make silly mistakes, it’s almost always a sign of switch tasking, not incompetence.

The third cost might not be quite so obvious. Remember how you felt the first time you did this versus the second time? Odds are you experienced a great increase in stress and frustration. The first time you did the exercise, I was calling out the time every five seconds, and it was no big deal. The second time, when I called out the time every five seconds, some of you probably yelled at your computer screen and said, “Stop! I’m trying to focus.” Why is that? This is the simplest activity in the world, yet when we introduce switch tasking into the equation, it becomes difficult, painful and laborious.

I want to share with you one last cost, and it illustrates the biggest cost that people miss out on. I want to give you an activity that you can do with your team, with your family. Have two people talk to each other. Person A tells person B for 30 seconds something that person A is passionate about ― a favorite hobby, favorite sports team ― and person B just listens quietly and patiently. Then you reverse roles. This time person B shares with person A something that they are passionate about while person A switch tasks by looking at their phone.

Do that for 30 seconds, and at the end, ask person B, “How did that make you feel?” When I do this with live audiences, the word that is almost always said is “unimportant.” Imagine that you start your day, wake up, go downstairs, see your significant other and say, “Hi, you’re unimportant. What are you going to do today?” Or someone calls your business, and you say, “Thank you for calling XYZ Financial, where you are unimportant. How can I help you?”

This is why an important thing to do is to always focus on the individual. This is the opportunity that you have. Because another word that I often hear when people multitask on each other is “normal.” Isn’t that sad? But, if you are someone who gives full attention, you stand out. And if your business does it, it builds stronger relationships.

There are four effects of switch tasking: the amount of time it takes to complete things increases, the quality of the work decreases, stress levels increase and the quality of relationships decreases.

Not next week, not a month from now, but today you have the opportunity to focus on people, giving them 100 percent of your attention and communicating to them that there is nothing more important in the world than them. That becomes a powerful differentiator in a world that is addicted to the myth of multitasking.

Dave Crenshaw develops productive leaders in Fortune 500 companies, universities and organizations of every size. He has appeared in Time magazine, USA Today, FastCompany and the BBC News. His courses on LinkedIn Learning have been viewed tens of millions of times. His five books have been published in eight languages, the most popular of which is “The Myth of Multitasking” — a time management bestseller. As an author, speaker and online instructor, Crenshaw has transformed the lives and careers of hundreds of thousands around the world.