-Intuition, even though Ne and Ni are different, I think N types find solace in other N types, especially in world where these traits are viewed as strange or bizarre. And even though my INFJ bestie will joke that I'm high when I jump from point A to Da Vinci Code*, I know he doesn't think of my mind jumps are a mental defect. But to some people I know, my Ne can really confuse them, especially my ESTJ mom. I love her to bits, but being around someone who thinks you're from a different planet is only fun for a little while before it just gets sad and lonely. . .
and moving on from that . . .
- The introversion . Both types understand the other's need for solitude and also the craving for meaningful social interaction. And combined with Ni or Ne, this equals unprecedented love for deep conversations. (with INFJ/INTP the Ti, Fe, and juxtaposition of Ni/Ne can take conversation to strange and wonderful places... *happy sigh*)
- INTJ's and INTP's even though they have all different cognitive functions, share commonalties as rational types and can be energized by deep intellectual conversations. And each offers a unique perspective, not just because individuals, but also because of function differences.
-And lastly the Flip-Side. With my INFJ friends (maybe its similar for INFP's for INTJ's) we are technically the introverted version of the flip side of our personalities. (me ENFJ at heart & INFJ -> ENTP at heart via A Little Bit of Personality) They understand and respect my introversion, but at the same time challenge me to develop the more caring side of my personality, Fe. And I offer up Ti, new perspectives with Ne possibilities. I notice I really push my INFJ best friend to consider different perspectives & be more openminded to other people's opinions, and he pushes me to think of other's emotions.
*Spoiler* if you are curious about that mind jump: