Let’s say you have a favorite customer who comes into your coffee shop twice a day, in the morning and afternoon. You always chat and catch up on each other’s day, you know about each other’s families and joys and frustrations with work. Then one day the customer comes in and says, “Hey I just wanted to let you know I’m moving so I won’t be coming in here any more.” Are you going to slam their coffee down on the counter and say, “Fine, leave then! Leave now!” Of course not.

Let’s apply that same story to the workplace.  You’re the boss of your organization (the coffee shop owner) and your best employee is the customer. You may be surprised to learn the “Fine, leave then! Leave now!” response is common with employee resignations. Of course, it’s natural to feel upset when an outstanding employee leaves. You’ve invested in this person. You’ve spent time together. You might have taken some risks on them. Now they’re just going to leave you? But this is when you have to pull out your grownup self and do what it takes to maintain good relationships with former employees, for several reasons.

1. Because you’re strategic.

   Like it or not, if you’re a manager or a business owner and you need to act like it. So while you likely have feelings such as: I’m upset, hurt and sad that this person is leaving and I really dread trying to replace them, you recognize that those are your uncomfortable feelings and it’s not the employee’s job to make them go away. Your job is to manage your own feelings and decide whether you want to try to keep the employee or how to positively move forward without the employee. Your focus is the good of the organization, not your feelings.

2. Because former employees could be your dream team, or your worst nightmare.

   Once that employee leaves your hallowed halls, they are no longer constrained in what they say about you. They could go out into the world telling everyone how great their experience was. They could recommend you on job boards, or to colleagues looking for work. They could talk you up to potential customers and business partners. They could be your best brand ambassadors. Or say you didn’t respond well to their decision to leave. Remember, it’s a small world these days with very few degrees of separation.

3. Because, more than ever, the only constant is change.

   About 10,000 Baby Boomers retire daily; Millennials switch jobs about every three years, and some reports show more than 70 percent of people are looking for new positions. Instead of being emotional about it, you need to figure out a way to tap into this reality and make it work for you. Some evolved companies actually form alumni groups for former employees so they can stay in touch with their co-workers, and the company and continue to make and receive referrals as everyone goes forward.

4. Because they might come back.

   Maybe they are moving to be closer to family, to learn a new skill your organization doesn’t need or, yes, for money. Their circumstances might change and they are choosing to return to you. They’re enhanced, value-added, new and improved. Its a unicorn! But seriously, wouldn’t it be great to say to them, “We love that you have those new skills and we welcome you with open arms.”

People want their work to be a place to grow in myriad ways—as humans, as well as employees, and earners. The most important thing is to understand why someone is leaving. Maybe they want to be closer to the grandparents. Maybe they want to try working in a startup, or in a big corporate firm, or for a non-profit. Maybe they’ve hit the ceiling in your company and you just need to find some other ways to make their staying more attractive.

But if you do manage to find a way for them to stay, you have to make sure that you’re managing your feelings there, too. Too often a manager will convince someone to stay and once the crisis has passed, they start getting mad at that employee. The employee has a target on their back after that, whether they and the manager realize it or not.

Every former employee is either an asset or a detriment. Most of the time, you decide which.