The most complex MBTI personality type to understand is likely the INTP (Introverted, Intuitive, Thinking, Perceiving) type. This is because INTPs are known for their analytical and logical nature, which can make them appear detached and difficult to understand for those who don't know them well. They tend to be introspective and independent, preferring to spend time alone or with a select few, which can make it challenging for others to get close to them. Additionally, INTPs are known for their ability to see multiple perspectives and their tendency to question everything, including their own beliefs and values, which can make it difficult to pin them down or understand their motivations.
Furthermore, INTPs are known for their love of abstract concepts and their ability to think outside the box, which can sometimes make them appear unconventional or rebellious. They may also struggle with emotions, both their own and those of others, which can lead to misunderstandings and miscommunications. All these factors combined can make it challenging for others to understand and relate to INTPs, making them the most complex MBTI personality type to understand.