Perhaps you know someone like our old business colleague. Let's call him Sam. When we worked with Sam, we spent time in each other's homes, went on international business trips together, helped each other's kids. Now and then, we'll send Sam a quick catch-up email or phone message, but he never responds.

The friendship is over, right? Not quite.

Every few months, out of the blue, Sam will email us. He'll begin by saying, "I've been thinking about you..." and his note will be warm, friendly, and peppered with questions about work and family. Happily, we'll respond within minutes and then ... wait and wait. Nada. Not a word back. So we'll call Sam and leave a message. Again, weeks pass with no response.

Chester's wife, Heidi, one of the wisest people we know, identified this phenomenon. She said, "He is careless with his relationships."

We're not the only ones dealing with a Sam. Every year our firm, The Culture Works, surveys tens of thousands of working adults about their engagement and satisfaction levels on the job. One of the biggest complaints we hear about teammates and bosses is that they are disrespectful. But it's often not the kind of disrespect you might imagine, like rude language, discrimination, or bullying. Instead, it's carelessness that is increasingly getting our hackles up.

When business people are late to conference calls, crotch-text in meetings, fail to respond to emails or phone calls, cancel appointments or don't show up at all, it sends a clear message: "I'll tolerate others, but they are not that important to me." Would anyone give his or her best work to a manager or colleague who was so careless? Hardly. So that message ends up trickling down to our collective employee engagement results.

Here's the simple truth: Many business people tell themselves they don't have time for softer things like worrying about relationship maintenance. They are busy executives, working in very serious industries, thinking Hey, I'm running a business here.

But even though everyone feels busier than ever, the most effective leaders we have studied all share a similar set of characteristics. One is that they give the people around them their full attention. That means doing simple, respectful things, like finding time at least several times a day to respond to emails, even if it's a quick, "I'm under water. Can we talk on Thursday?" And most of these leaders have an astounding ability to concentrate on the task at hand.

Take this example: On Super Bowl Sunday last year, we were asked to speak to the global marketing leaders of Intel about building employee engagement in their teams. Given the timing of the game, we were surprised that during the workshops, not one executive, not once, looked down at his or her phone. It was so surprising that we asked one of the organizers about this phenomenon.

"Oh, we'd never do that," he said. "It's part of our culture that we give 100 percent of our attention to what we are doing. If we are in a meeting, we are 'all in' the meeting."

It's a great practice from a company that has continued to be innovative and relevant in a very, very challenging industry. Any coincidence?

Becoming more considerate and less careless won't just make our moms proud. It's a simple thing we can all do to positively impact our careers and businesses, building powerful relationships for years to come.