If your best-performing employee quits, it's on you. That's what Jeff Weiner believes.

As Weiner mentioned in a September CNBC interview, all employees want the same thing: to have a manager who cares about them and does everything in their power to set them up to be successful.

So what happens when your employees feel that their managers don't have their backs? They jump ship.

Now, if I ask you to think of a "bad manager," you'll probably come up with an image of a bully who likes to micromanage their staff, and never lets anyone take any time off. You're nothing like that person, so you can't be a bad manager. Right?

Well, not exactly. If you're guilty of delegating tasks to your team members without taking the time to mentor them, you could be seen as a bad manager, too.

Weiner says the problem arises when employees feel as though their managers don't have time to invest in them. Look at it this way: If you've never shown any interest in your team's personal development, or asked them what they want to accomplish in their careers, it's easy for them to feel like a cog in a machine.

You can retain A-players (and allow them to work at their best).

If your goal is to create an environment where employees can do their best work, it's important to help your employees form a sense of belonging. It's not rocket science. Having a sense of belonging increases job satisfaction, and job satisfaction in turn increases performance and retention.   

Ideally, you should ensure that all your employees are happy. This is especially important for your superstar employees.

Everyone wants to hire superstars, so you should assume that your competitors are trying to poach your best employees every week. How do you make it easy for your superstars to choose to stay?

First, make sure you recognize them and appreciate their contributions to their company. Next, talk to them about their goals and let them know they've got space to grow in your company. You want them to think of their current gig as a long-term career option, not just a stepping stone.

I also like to make sure I screen new hires properly and make sure they're a good fit. Superstars like to work with other superstars, so if you hire folks who have bad attitudes and can't get their jobs done, chances are that your best people will get frustrated and leave.

The bottom line: Invest more time in your employees.

Look, I get it. It's easy to get caught up in busy work (replying emails, sending invoices, fighting fires). You've got to learn how to prioritize, and set time aside to mentor and groom your employees.

At the end of the day, the goal is to build up an amazing team of rock stars who you can trust to work independently and make the right decisions for your company. Start working toward that goal today.