In Mary Shelley's Frankenstein, there are several passages that indicated how the creature's heart has been "contaminated" by society.
In Chapter Ten, Victor confronts the creature, who speaks to his creator for the first time. First the creature says:
All men hate the wretched; how, then, must I be hated, who am miserable beyond all living things!
Then he alludes to how he has been treated by mankind. He says:
You, my creator, abhor me; what hope can I gather from your fellow-creatures, who owe me nothing? they spurn and hate me.
I was benevolent and good; misery made me a fiend.
This foreshadows the part of the the monster's tale of what happens to him, innocent as a newborn baby, when Victor flees his creation and the creature ventures into society, only to be attacked. We can also see that he is being contaminated as we compare his wishes to be kind to others and accepted by them, only to receive violence and rejection.
In Chapter Eleven, the creature comes face-to-face with a man who flees at the sight of him, alluding to the first of many incidents where the creature is alienated from the human race because of his fearful countenance:
Finding the door open, I entered. An old man sat in it, near a fire, over which he was preparing his breakfast. He turned on hearing a noise; and, perceiving me, shrieked loudly, and, quitting the hut, ran across the fields with a speed of which his debilitated form hardly appeared capable.
Later, the creature moves travels to another village with beautiful houses...
One of the best of these I entered; but I had hardly placed my foot within the door, before the children shrieked, and one of the women fainted. The whole village was roused; some fled, some attacked me, until, grievously bruised by stones and many other kinds of missile weapons, I escaped to the open country...
The experience that is most hurtful comes in Chapter Sixteen at the hands of Felix and his family. The creature has secretly observed them, learned from them and become quite fond of each member of the household. He approaches Felix De Lacey's blind father first, who welcomes the monster. When Felix and the others arrive, Felix drives him out violently, and then they all flee, leaving the creature to feel more isolated than ever. His heart is broken by the way he is treated by other creatures of society, even though he has no ill-intent, and never sets out to hurt anyone.
At that instant the cottage door was opened, and Felix, Safie, and Agatha entered. Who can describe their horror ...on beholding me? Agatha fainted; and Safie, unable to attend to her friend, rushed out of the cottage. Felix darted forward, and with supernatural force tore me from his father, to whose knees I clung: in a transport of fury, he dashed me to the ground and struck me violently with a stick. I could have torn him limb from limb...But my heart sank within me as with bitter sickness, and I refrained. I saw him on the point of repeating his blow, when, overcome by pain and anguish, I quitted the cottage and in the general tumult escaped unperceived to my hovel.
It is easily to see that the creature has a capacity to love. When Felix beats him, the creature notes that he could have easily destroyed him, but did not because he cared for him. Victor's "experiment" is devastated again by society's rejection, and it is these kinds of incidents that drive the creature to behave like a monster.