In order to be able to analyze the ways in which Shakespeare leads us to both like and dislike Shylock simultaneously, it is essential to realize that The Merchant of Venice was written at a time when, there existed in England, an enormous prejudice against Jews and other minorities. Throughout the play, Jews are described in highly derogatory ways (e.g. "the dog Jew"), which are not necessarily meant to describe Shylock in particular, but are aimed at his race as a whole. The obvious anti-Semitism portrayed in this play is almost certainly as a result of Shakespeare's ignorance since Jews were expelled from England in 1290, therefore Shakespeare would probably of never have even met one.
In Acts I and II, there are only a few examples of Shakespeare's feelings towards Shylock. No doubt, a fuller picture will emerge in later acts of the play.
One cannot help but be sympathetic to Shylock when he describes how Antonio has mistreated him in the past. Apparently, Antonio had scolded him about being a moneylender and charging interest. He had called him a "cutthroat dog" (I, III, 35) and he had spat on his beard and on his clothes. Yet after all of those insults Shylock says:.
""Hath a dog money? Is it possible a cur can lend three thousand ducats?" Or shall I bend low, and in a bondman's key, with bated breath and whisp"ring humbleness say this: "Fair sir, you spet on me on Wednesday last; You spurned on me such a day; another time you called me "dog" and for these courtesies I"ll lend you thus much moneys?"" (I, iii, 35).
Shakespeare portrays Shylock in a negative way with reference to the gruesome bond that Shylock demanded for his three thousand ducats loan to Antonio. The disgusting and outrageous idea of demanding a pound of human flesh in all probability reflects the anti-Semitic fantasy of Jews being prone to violating Christian bodies.
Similarly, Antonio mocks Shylock's in depth knowledge of the bible when he says to Bassanio when commenting on Shylock's biblical story regarding Jacob that, "The devil can cite the Scripture for his purpose! An evil soul producing Holy witness is like a villain with a smiling check, a goodly apple rotten at the heart.