Nick's experiences would certainly have served to change his perspective and outlook on life. When he returned to the Midwest, he was likely less trusting... and possibly a bit more judgemental. I believe that Nick welcomed his return to midwestern values, solid living, and real people. The opulence of the East Egg was surely intriguing...... but it wasn't real, and I don't think that he ever would have embraced the false faces and lack of morality permanently. Nick was star struck..... money, parties, beautiful women, but during his time in New York he'd had enough. I'm sure that when Nick established a home, family, and good friends..... trust would have been an integral part of his relationships. I think he probably became known as a real stand-up guy...... a good man.