in your opinion, what kind of people are they?

In general these are people who use one lie after another to cover up either an ugly truth they do not wish to face, or to make themselves sound better and grander than they really are. Gatsby does know some rich and powerful people; yet his claim of a Midwestern upbringing does not jive with his statement about being born in San Francisco. Gatsby has told Jordan that he is in love with Daisy, revealing a past which he has not discussed with Nick. He meet a shady, sort of unseemly character in Wolfsheim who is probably associated with organized crime.