Maybe you've heard stories about the wacky things modern companies like Amazon and Google ask job applicants.

"What song do you want played when you walk into a room, if it could only be one song for the rest of your life?" "What kind of tree are you?" Stuff like that.

They obviously think these kinds of questions will help identify the people who are the most creative, ambitious, out-of-the-box thinkers, which is the personality type these tech companies are looking for.

The very fact that one in five Fortune 1000 companies uses Myers-Briggs Type Indicator testing shows that smart leaders in all kinds of businesses also want to get to know their employees beyond the surface. Probably you have done something similar, and that's smart.

But think about what you're trying to achieve by knowing whether your employee is an introvert, a highly divergent thinker, or an obsessive-compulsive. It does tell you a lot about what makes a person tick--but do you know why you need to know that?

Here are three reasons it's essential to find out about as much as you can about the way people on your staff think--not just professionally, but deep down in the nooks and crannies of their personalities.

1. To Create a Cultural "Fit" That Fits

You want to build a corporate culture that takes you straight to the top, right? Basically, that's what it boils down to, whether you're running a nonprofit organization to help kittens or a multinational brokerage firm to help the people that own kittens. Either way, you want people to feel they belong, are appreciated, and can make a contribution. You want, ideally, a culture where everybody is engaged and happy and sniping is kept to a minimum.

Ask the questions and do the tests, but also pay attention to whether Janine is writing a novel in her spare time or Shawn is taking night classes in management. Notice that Jeff gets stressed out by noise around his work area and Harriet frequently walks around with headphones in, bopping her head to music. Maybe you can give Janine the newsletter assignment, invite Shawn to a managers' meeting, put Harriet in charge of the Friday parties, and let Jeff work from home once a week.

When people feel "seen" and understood, that not only becomes part of your culture, but your brand as well.

2. To Get and Keep the Best People

Don't treat your candidate interview like a speed-dating session where you're trying to impress each other in the shortest amount of time. Slow down, notice,  and really take a look at whether this person will be happy at your company over the long term. Don't just expect applicants to think outside the box; do it yourself, too. If it takes asking "What kind of tree are you?" then so be it, but try to draw out the applicant and get some idea of his or her real personality under the window dressing.

Consider that a person who might be unhappy in one job might blaze new trails somewhere else at your company. Consider that if mid-career Melanie seems to be applying for a job that's a lateral move in a whole different business, maybe something important has changed in her life or she has decided she wants to change things drastically.

This is sometimes the reason for rejecting someone as "overqualified," but you can do better than that. Give her the chance to explain herself before you toss her resume in the can.

And even with people who have been in a job for years, there's time to revisit that person's "fit" in relation to others on the team. You might even need to move people, perhaps even the most talented ones, to a different job where their quirks become strengths and their needs are more closely aligned with their co-workers.

3. To Make Work a Growth Exercise for Everybody

Suppose you have carefully spent time talking one on one with people, and--perhaps even more important--watching and learning from their actions. You've moved people to better situations, given them new challenges, and said goodbye to one or two who just did not have a place with your company. Are you done?

Of course not.

Whatever "kind of tree" your business is, it will always need a lot of water, pruning, and plant food applied by its leadership. That's how trees grow. And, metaphorically speaking, it's how people grow, too.

If you're appropriately challenging people, they will eventually change and need to go somewhere fresh.  Make sure you are cultivating opportunity within your own company so they won't need to take everything they've learned working with you to another business.

Published on: Feb 20, 2019
The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.