The father-son relationship
In the Death of a Salesman, Willy Loman has a difficult tense relationship with both of his sons Biff and Happy throughout the play. He sees that they have not grown as he wished.
However, Willy does not realize that he has not instilled a sense of responsibility, work ethic, or morals into Happy and Biff.
This relationship is a turbulent because it lacks the limitation of affection and respect that should exist in a healthy relashionship between a parent and sons. Specially with Biff, Willy builds him as a more handsome and successful in order to re-live his lost years. Ignoring Biff's wishes and possibilities. Because of Willy is unable to accept the miserable reality of his live, Biff sees himself as trapped in Willy’s grandiose fantasies. He struggles against the force of Willy’s dreams and expectations. 
Even when he attempts to bring Willy out of his delusion and determines to break all lies in his family, saying that " we never told the truth for 10 minute in this house".
As a result, the dissociation and turbulence role the backbone of the Loman's relationship.
Rather than seeking to enable the family move forward, they basically go head-on against each other.