Fitzgerald describes Nick as non-judgmental, that he knows not everyone has had the same advantages he has had in life which helps him befriend and understand people.
Because Nick is the narrator, it is important to set the character up in this way because the reader will be more likely to trust the observations of the other characters that Nick makes. If the reader thinks he is too judgmental, they might not believe his story as fully.
Morpheme is the smallest meaningful unit of language structure.
affix is something placed at the beginning or end of something that changes the meaning.
suffix is placed after the word to change the meaning.
prefix is placed at the beginning of the word to change the meaning.