Certainly Shylock can be presented in a negative way, but it is interesting how more recent interpretations of the play try to present how he has been wronged whilst perhaps softening the criticism against him. Let us remember that he does 'have cause' for pursuing his revenge, even though it comes to possess him.
A further example of these sins also revolves around the treatment of his daughter, Jessica. In fact, Shylock treats her as one of his belongings, valued less than his money or gems. In Act II, Shylock tells Jessica to "Lock up my doors...nor thrust your head into the public street to gaze on Christian fools." He abhors the Christians so much he orders Jessica not to even look at them.Ironically, Jessica has already planned to elope with a Christian: "Farewell...I have a father, you a daughter lost" (2.4.56-57). Upon hearing of his daughter's flight, Shylock's avarice and wrath are apparent: "I would my daughter were dead at my foot and the jewels in her ear!" (3.1.95-96). Shylock is so eroded by his greed that his only flesh and blood becomes meaningless when compared to his wealth. It is shortly after when Shylock reveals to the audience his envy of the Christians. In speaking of Antonio he states, "He hath disgraced me...scorned my nation...and what's his reason? I am a Jew"(3.1.57-60). Shylock is so twisted by his own prejudice against the Christians that everything becomes an issue of Jew vs. Christian.Thus, you see the worst characteristics of Shylock in his relationship with his daughter and the many ways that greed leads to his ruin.
Shylock exhibits all of the negative, stereotypical traits anti-Semitic people ascribe to Jews, and as such, everything Shylock does and says is an example of his envy, greed, and anger. His love of money is evident throughout the play. Part of his hatred toward Antonio stems from the fact that Antonio loans money and doesn't charge interest. This forces Shylock to lower his interest rates. I believe the main reason Shylock hates Antonio, however, is because he says Antonio has made fun of him, spit on him, and found pleasure in his failures. Shylock wants revenge for this treatment, and his hatred of Antonio is evident. This is why Shylock refuses to take the 6,000 ducats offered to him at Antonio's trial. He is a miserable man who cannot even stand to hear the music played at the ball held by the Christians. In the end, Shylock's evil is his own undoing. His money and his faith are taken away from him, and he has nothing left.
Enotes has a general and a detailed summary of the play, along with a character analysis of Shylock. Go to the link below and you'll find many more examples of Shylock's greed and hate.