“A package for me!” Without fail, this is my gleeful mental exclamation whenever I spy a parcel near the mail slots at my apartment complex. Logically, I realize the odds are about 1 in 84 that the package will actually be for me…but such cold logic doesn’t stop my knee-jerk expectation that disappoints 83/84 times.

Similarly, I’ve noticed people hold another hidden assumption that causes them recurring disappointment. It’s often operating at a semi-conscious level, but for most people, it’s there. Articulated, this assumption sounds something like: “People are more or less similar to me.”

But the odds are they aren’t. This disappointment often manifests itself when we perceive a teammate to say something that appears off-kilter. When people say things that seem to miss the mark, it’s often because they naturally operate their brains in a way different than our own.

Contrast the similarity assumption to that of psychologist Carl Jung and his devotees Isabel Myers and Katherine Briggs Myers. They believed that each human is born with a distinct psychological type. (“Now you don’t have to buy that” noted my Myers-Briggs sensei during my certification. Indeed not, but this simplifying assumption can sure prove useful!)

This crew catalogued these psychological types by identifying mental preferences across four dichotomous scales. This is often done with an instrument called the Myers-Briggs Type Indicator (MBTI). The MBTI is a Cadillac of psychological tests, having been refined across decades of research…but you can take a quick-and-dirty, semi-accurate knock-off at Human Metrics.

The four scales address the questions:

• Where do you get your energy? Extraversion (externally, from people, broad affiliation) OR Introversion (internally, from deep thought, intimate conversation)?
• How do you gather information? Sensing (observation, facts, experience) OR iNtuition (imagination, patterns, theories)?
• How do you make decisions? Thinking (logic, analysis) OR Feeling (empathy, values)?
• How do you handle your business? Judging (schedules, systems, plans) OR Perceiving (spontaneity, flexibility, adaptation)?

You may have seen or heard a four-letter combination describing one the sixteen types created by taking one letter from each of these questions. You might hear in conversation, “I’m an ESTJ” or “I’m surprised that you’re an INTP.” These abbreviations refer to which preferences a person exhibits on each of the four questions. So, one whose preferences are ESTJ prefers Extraversion, Sensing, Thinking, and Judging.”

While these four letters are pretty telling in themselves, there’s a dynamic interplay among them that can tell a rich story, capturing much of how you operate. Check out some of the free descriptions of the type that likely matches you; the results may be downright freaky. (Or maybe I just like my description because it says that ENFJs have “tremendous charisma.” I hope my audiences think the same thing!) Or, if that’s too serious and personal, you can warm up by seeing how psychological types align to your favorite Simpsons characters. I think it’s fair to say that Apu and I have a lot in common.

Working through the Myers-Briggs, it’s a thrill to see teams reach a new level of mutual understanding. The “eureka!” moments emerge as people embrace a tool to explain what they previously thought was a defect in themselves or a teammate. For example: “Oh, it’s not that my boss distrusts my work when he asks questions about seemingly tiny things, he’s just naturally drawn to certain details (sensing), whereas I’m more of a big picture kind of guy (intuition).”

Of course, every tool has its limitations. My friend Justin once mused, “What would it take to have the ultimate profile of a person? I suppose you’d have to collect everyone’s Myers-Briggs, Enneagram, and StrengthsFinder…along with a blood sample, urine sample, and stool sample.”

While the conference-loving dork in me revels in imagining such a complete profile, I have to concede that humans are more complicated than any small set of categories. Whether you group people into four humors like the ancient Greeks, sixteen types like the Myers-Briggs, or identify folks’ top five strengths like Gallup…you can’t capture it all. But you sure can capture surprisingly much  with a small number of categories!

Having used multiple approaches, the Myers-Briggs reminds me of Goldilocks’ porridge. 6.8 billion unique humans is pretty overwhelming…while viewing only four personality types can over-simplify. For me, the MBTI’s sixteen combinations are just right.

So the odds are…your teammate’s type is not yours. But, unlike the enticing package belonging to your neighbor, this mental diversity can be a source of power—instead of disappointment.