Point 1:  O!nly cares about himself.

Proof 1: “ I told him the truth...He was crazy enough to kill me if I hadn't told him who owned the car. His hand was on a revolver in his pocket every minute he was in the house”

Explanation 1: Makes Wilson believe that Myrtle was Gatsby’s mistress and made Wilson believe that he killed Myrtle; leading to Gatsby and Wilson’s death.
 

Point 2: Tom Buchanan has no morals.

Proof 2: “And what’s more, I love Daisy too. Once in a while i go off on a spree and make a fool of myself, but I always come back, and in my heart I love her all the time.”

Explanation 2: Tom admits to having affairs, but he thinks its alright because he always comes back to Daisy and he stills loves her.

Point 1: He trusts Daisy and she is careless.

Proof 1: "I don't think she ever loved him…...She hardly knew what she was saying” 

Explanation 1: Gatsby puts all his trust into daisy(who is very careless) believing in her love for him. Then she takes back her promises.

Point 2: He is too invested in his dreams.

Proof 2:  “...but of course I'll say I was.”

Explanation 2:  Gatsby was so blindly in love with daisy and his dream that he carelessly took the blame for something he didn't do which ultimately got him killed.