INTP:
INTPs lack follow-through and this can isolate their ideas from practical examination. Their notions become over-intellectualized and too abstract to be of practical benefit. With their sharp critical thinking and analytical abilities, INTPs tend to nit-pick, hair-split, and generally overdo simple issues. Their desire for accuracy and precision exacerbates any error they may perceive in themselves or in others — they are, in other words, highly self-critical. Wanting to be competent and know everything, their standards grow increasingly higher. When fear of failing becomes overly pronounced, INTPs are quick to feel unintelligent, slow, and powerless.
If stress continues, the INTP's mind seems to freeze and block out the vital information it has worked so hard to accumulate. Their creative juices stop flowing and they suffer from stage fright, writers block, and a general inhibition of their ingenious thinking and fluent language skills. Preoccupied with performance failure, INTPs become self-consciously distracted in anticipation of their failure. If the stress becomes too overwhelming, the fear of blanking out prevents them from taking risks in areas they desire to succeed in. Attempting to avoid incompetence, they fail to gain the expertise and mastery they so desperately need.
INFP:
INFPs feel internal turmoil when they find themselves in situations in which there is conflict between their inner code of ethics and their relationships with others. They feel caught between pleasing others and maintaining their own integrity. Their natural tendency to identify with others, compounded with their self-sacrificial dispositions, tends to leave them confused as to who they really are. Their quiet personalities further feeds their feelings of depersonalization. The INFP's quest for self-identity then seems even more alluring — but increasingly impossible to attain.
As with all NFs, the INFP will feel lost and perplexed at stressful times. As stress builds, INFPs become disconnected from their own personality and perceived place in life. They will lose sight of who they are in relation to time and place. They may not make basic observations, while instead they will focus on the more abstract and symbolic meanings of a particular interaction. This can sometimes baffle those who expect more direct communication and a fairly concrete relationship.