As a CEO, I get asked this a lot. And, I’m always a little embarrassed by it. For the most part, I get the question from people who are in their twenties. They want to know “the secret path to the top.”

This past weekend, I received an email from one of my readers. He started, “I have an MBA, but I must have missed the course on Fast-Tracking My Career. If you had to boil it down to one thing, Mr. Hyatt, what would you recommend to a young, aspiring person such as myself?”

I’m not sure I could boil it down to one thing. Life isn’t usually that simple. But if I really, really had to boil it down to one thing, I would say this: responsiveness.

So many people I meet are unresponsive. They don’t return their phone calls promptly. They don’t answer their emails quickly. They don’t complete their assignments on time. They promise to do something and never follow through. They have to be reminded, prodded, and nagged. This behavior creates work for everyone else and eats into their own productivity. Sadly, they seem oblivious to it.

When I was a kid, we used to play “Tag.” The objective was simple: keep from becoming “It.” If someone tagged you (touched you), you became “it” until you tagged someone else. Whoever was “it” when the game ended, lost.

Business is very similar. People “tag” us in countless ways every day. They place calls. They send emails. They mention something to us in a meeting. Suddenly, we are “it.” And, just like the game, if you stay “it” too long, you lose. The only winning strategy is to respond quickly and make someone else “it.”

Reality is that we live in an “instant world.” People want instant results. They don’t want to wait. And if they have to wait on you, their frustration and resentment grows. They begin to see you as an obstacle to getting their work done. If that happens, it will begin to impact your reputation. Pretty soon people start saying, “I can never get a timely response from him,” or “When I send her an email, I feel like it goes into a black hole,” or worse, your colleagues just roll their eyes and sigh at the mention of your name.

Yet, these are the very people who will push you up or pull you down. You cannot succeed without the support of your peers and subordinates. (Go back and re-read that sentence again.)

As I was making my way to the top, my former boss, Sam Moore, used to ask everyone I worked with, “What’s it like to work with Mike?” “How’s he really doing?” “Do you think he could take on more responsibility?” In responding to him, all they had was their experience with me. If I hadn’t been responsive to them, how do you think they would have responded to his questions? “More responsibility? Are you kidding me? He can’t handle what he has now!” It wouldn’t take too many candid responses like that to tank my career.

And yet this happens to people all the time. I can’t tell you how many meetings I have sat in where people are complaining about someone else’s work habits. “He always waits until the last minute.” “She never plans ahead.” “I can never get him to respond to my emails.” You may think that the people who are making these comments are too far down the food chain to matter. I can assure you they aren’t. They have a way of bubbling to the top where the decisions about your career are made.

The truth is, you are building your reputation—your brand—one response at a time. People are shaping their view of you by how you respond to them. If you are slow, they assume you are incompetent and over your head. If you respond quickly, they assume you are competent and on top of your work. Their perception, whether you realize it or not, will determine how fast your career advances and how high you go. You can’t afford to be unresponsive. It is a career-killer.

My basic rule is this: respond immediately unless there is a good reason to wait. Obviously, this isn’t always possible, especially since I spend so much time in meetings. Nevertheless, I rarely let messages sit longer than a day. Twenty-four hours is the outside edge. If you can’t respond now, then at least acknowledge that you have received the message: “I received your message. I don’t have time to give it the attention it deserves right now, but you can expect to hear from me before the end of the day tomorrow.”

The great thing about being responsive is that it will quickly differentiate you from your peers. People love doing business with responsive people. Nothing will advance your career faster than this.