Just by relating to one another doesn't make everyone is rightly typed .. it just makes it possible that everyone is the same type, but just not the one they're thinking. So don't go by relational typing - and do heavy duty research into Cognitive Functions.
Look at the following:
1. Direction of energy --- Is it external, or internal? Think first, speak later? Speak first, think later?
2. What is the external environment like --- Is it forcing you into periods of isolation. The human mind is flexible, if the environment is not conducive to extroversion, then the mind will adapt to introversion, become used to it, believe it to be a preference even when it is not. It is possible.
3. Getting "bored" of extended interaction is not the same as getting "drained" by it - I've seen a lot of potentially extroverted people claim to be introverts because they don't want to socialize with specific types of people ... It's the next best thing to being alone right? It's so easy to just believe that "I like being alone because I can do a shitload of activities when I'm alone and I don't mind it because I'm entertained." >>> Big clue to a potential mistype .. just because someone can entertain/distract themselves when they're alone is also not an indication of introversion.
INFJ's = NiFe .... Everything is filtered through intuition.
ENFJs = FeNi .... Everything is filtered through feeling.
There's a lot of good resources in the Cognitive Functions forum now ... much better to research there, than try to relate within sub-forums, because if there are 20 people here and 10 of them are mistyped, then they are potentially causing others to mistype as well.