why did Farid dislike Amir?

Farid had two wives and seven children, two of whom had been killed by a landmine. Farid himself was missing toes and fingers from his years of combat. Farid was suspicious of Amir because he saw him as a defector; whereas Farid had stayed and fought for his homeland, Amir had fled to the privileges of America. He had abandoned his watan, his homeland.