Whenever someone does something or is going to do something for gatsby, what does he do? what does this reveal about gatsby?

He always tries or wants to pay them back in some sort of way. For example, when Nick invited Daisy over for the tea party, Gatsby tried to get him involved in something that would help him make more money. It shows that Gatsby probably feels like he is less than enough which would lead him to believe that he needs to give people a reason he is important enough for a favor.