Nines and Twos can easily mistype. It is especially the case that female Nines who are identified with a nurturing role might mistake themselves for Twos. Both types tend to be generous and oriented towards feelings and relationships. Nines, however, are truly humble and generally self-effacing, whereas Twos tend to have a high opinion of themselves and tend to want to receive recognition for their good deeds. Twos are also far more aggressive when pushed than are Nines who characteristically withdraw under stress.
Nines and Fours can both be sensitive, creative, withdrawn and introverted and for these reasons can cross-type, although it is generally the Nine who mistypes as a Four or who is mistyped as a Four by others on the basis of these similarities. Nines, in particular, sometimes recognize that they are far less happy than they let on, and many Nines feel inadequate when depressed; they therefore think they must be Fours. The internal landscape of Fours is much darker than that of Nines however, who tend to see the best in others and who characteristically detach from strong emotions, especially strong unpleasant emotions. Nines are also not in search of an authentic self or the proper presentation of that self; they are generally somewhat oblivious to these concerns. Finally, Nines tend to relate well to a greater variety of people than do Fours, who often feel like misfits.
Nines and Fives are both withdrawn types and many Nines are systematic thinkers and intellectuals, therefore there are some commonalities which might generate a mistype. It is generally Nines who mistake themselves or are mistaken by others as Fives; Fives almost never mistype as Nines. One of the principle differences lies in their approach to thought. Nines tend to look for thought systems which offer some sense of harmony; Fives are attracted to what disturbs them and often embrace or struggle against nihilism. Nines relate well to a wide variety of people; Fives to only a few.