For example it can be hard to tell the difference between ENTJ and INTJ that is showing its social side. Unless we are talking about very E and very I.
If I were to doubt my type my second choice would be ENTJ.
I am very introverted person but I also have very well developed NTJ part. Which is constantly spilling over the introversion. That is why I never become total isolationist.
But instead I created connections with few people so that I get informations and I aways know what is going on. You can't call that exactly a friendship but it is social connection.
So my NTJ part makes me quite unusual introvert. Since I am not shy or socialy paranoid what is typical for introverts.
What can be quite intimidating since no one expect that much directness, hostility,criticism and organisation from so introverted person. If I show my "cards" I usually do it with an element of suprise.
But with ENTJ you more or less know where you are since they are far more open and they get along with people better since they are people oriented they can never become so cold as INTJs since people have problems with that.
What we share is desire to control, understand and improve systems, good selfesteem and long range big picture thinking.
I always looked at diferences between the two like:
ENTJ- Supreme Commander of armed forces
INTJ- Director of intelligence agency
They're strong, purposeful, always on a mission... and every time I meet one I can see them scanning me. And I can feel myself scanning them too. And it's a strange stand-off, like a bridge can't be made.