I first learned about the Myers-Briggs type indicator (MBTI) about five years ago, but my result of ISTJ just didn’t click with me—and there’s a good reason why: I’m actually an INTJ, but one of the many free tests available online mistyped me. And it turns out, this is a relatively common mistake.

“People can be mistyped due to surroundings,” says Ann Holm, a career coach and Myers-Briggs master practitioner. “Behaviors can be impacted by family, country of origin, education, life experiences, and the opportunities you’ve had to actually use your type.” I grew up in an ultra-traditional, ultra-conservative small town, and Holm says this may mean that I didn’t have as much opportunity to use my natural preference for intuition, thus leading to being mistyped.

Back when I first felt misunderstood by my first Myers-Briggs results, I decided to take the official Step II Myers-Briggs examination, administered by a master practitioner (you can also take the official test online). The test confirmed my basic type as an INTJ, through and through, and also landed me a 17-page report about how I compare to other INTJs.  Here are a few things I from that report, and from speaking with MBTI pro Holm about it, that may blow your personality-type-obsessed mind.

1. Your MBTI type preferences aren’t necessarily all strong

The Myers-Briggs model includes 16 personality types and four preferences within those types. Those preference scales go as follows:

• Extraversion or introversion (E or I)
• Sensing or intuition (S or N)
• Thinking or feeling (T or F)
• Judging or perceiving (J or P)

For the most part, my type (INTJ) preferences for introversion (I), intuition (N), thinking (T), and judging (J) are strong, so I am an “in-preference INTJ.” But every once in a while, says Holm, INTJs who may act more like Ps (perceiving) than Js (judging) or Fs (feeling) more than Ts (thinking) in certain facets of their personality on those respective preference scales.

So, though there are 16 personality profiles of MBTI, there are more than 16 types of people. So who you are within your MBTI archetype will still likely look different than someone who shares your four-letter combination.

2. MBTI cognitive functions can be a source of confusion

Your auxiliary function (second function) is confused with your dominant function

Each Myers-Briggs type has eight corresponding cognitive functions, referred to as a “stack.” In practice, MBTI cognitive functions range from the most-preferred function to the least, and the most important of the stack are the top two: the dominant and auxiliary functions. In my case, INTJs favor introverted intuition (Ni) and extroverted thinking (Te). This means that I like to see the big picture, or perhaps the entire puzzle board, and I like to understand how every piece fits and works together in that complex whole. To explain what I think, I use systems, logic, and direct language.

But since my dominant function is introverted, my extroverted auxiliary function can sometimes present in a louder, more obvious way. What others see isn’t the way I process information in my mind, but rather the external manifestation of that. Though my extroverted thinking (Te) auxiliary function is often most clear socially, it can also skew a bit underdeveloped compared to the traits of dominant-function extroverted thinkers (ENTJs and ESTJs). And perhaps, this is why I’m prone to saying the wrong thing or feeling like I can’t find the right words to convey my thoughts.

Your perceiving and judging functions are misunderstood

Every type also absorbs information differently. Some are quick to make conclusions, while others sit back, observe, and analyze. This quality is what the difference between P (perceiving) and J (judging) seeks to explain: You’re either a dominant perceiver or a dominant judger.

If you are an extrovert, your dominant function matches your last letter. So, an ENTP is a dominant perceiver (extroverted intuition, Ne, is a perceiving function), and an ENFJ is a dominant judger (extroverted feeling, Fe, is a judging function). Introverts are flipped: their dominant function is opposite their last letter. So, an ISFJ is a dominant perceiver (introverted sensing, Si, is a perceiving function), whereas ISTPs are dominant judgers (introverted thinking, Ti, is a judging function).

As an INTJ, I lead with my introverted intuition (Ni), although what others see most often is my extroverted thinking (Te), as mentioned before. But my introverted function (Ni) is all about studying, theorizing, and waiting for knowledge and information to come to me, before I jump out there and make conclusions (Te). This means, I am a lot more open-minded than I appear on the surface—and ENFJs or INTPs might be a lot less open-minded than they appear initially, both as dominant judging types, despite only one displaying that telltale “J.”

3. Endless other reasons

Many MBTI types have their own idiosyncrasies that may lead them to mistype. For example, Holm says ISFPs are adaptable to their surroundings to a fault, which can lead to error. Then there are the EXXP types that are dominant perceivers—ESTP, ESFP, ENFP, ENTP—who may all struggle to make up their minds. And while worlds apart in terms of how they behave in the world, ESTPs and INFPs are both uniquely sensitive, which can lead to each being confused with other types: INFPs have strong values and emotions that inform everything they do, but their introversion can mask this reality. And ESTPs are highly sensitive to sensory details, like sight, sound, taste, and smell, which can sway how they feel about a given situation.

All of this is to say there are many reasons you may feel your MBTI results don’t describe you aptly. But whether you’ve been mistyped or simply could use some assistance understanding the nuances of your specific profile is what remains to be seen. Learning more about the official test (and actually taking it) in addition to seeing a master practitioner to talk through your results are good places to start on the journey to clearing up what makes your personality type completely unique.

Want more Myers-Briggs intel? Here’s the biggest stereotype for every personality, debunked. And here’s what you were like as a kid based on your MBTI.