INFJ/INTJ people (or others types!!) give me your take on Ni!

Ni is often misunderstood, or not understood at all. So tell me your thought! Could be what you think it is, how it transcribes in your/someone you know's daily life... etc.
If you don't know about MBTI, here is a very cool test! (Not long, but accurate.)
https://jupiter-34.appspot.com/

The only way to type yourself correctly isn't through tests, it's through introspection, sometimes you don't know the answer to a question, that's why you should keep it in mind until you're able to answer it. it's crazy how MBTI helps understand oneself. Also, you cannot type yourself before you fully understand the jungian functions! Here's a good link:

Here's a link:
https://www.intpforum.com/threads/cognitive-functions-100-basic-functionality-revised.6582/