What did Happy’s behavior in the restaurant before Biff arrived reveal about his character?

At the restaurant, Stanley the waiter seats Happy. A lavishly dressed girl enters and sits at the next table, and Happy tells Stanley to bring her champagne. Biff enters as Happy flirts with the girl, who is named Miss Forsythe. Happy tells Miss Forsythe that Biff is a quarterback with the New York Giants. Happy asks the girl out, and asks her if she can find a friend for Biff. While Biff's failures and flaws have been a major preoccupation throughout the play, this segment demonstrates how detrimental Happy's character flaws can be. A compulsive womanizer, Happy tells blatant lies to the women that he meets, claiming that Biff is a professional athlete, then gets rid of his father in favor of seducing Miss Forsythe. In the final, most cruel move that Happy makes, he denies that Willy is his father, thus repudiating his father even more callously than Biff has done.