Judgement based on physical appearance, failure to understand the warm "man" on the inside.
"flash of lightning illuminated the object and discovered its shape plainly to me; its gigantic stature, and the deformity of its aspect, more hideous than belongs to humanity, instantly informed me that it was the wretch, the filthy demon to whom he had given life." Chapter 7, pg. 60
Longing to be accepted and loved, the monster hates himself and outer image.
Hateful day when I received life!' I exclaimed in agony. Accursed creator! Why did you form a monster so hideous that even YOU turned from me in disgust? God, in pity, made man beautiful and alluring, after his own image; but my form is a filthy type of yours, more horrid even from the very resemblance. Satan had his companions, fellow devils, to admire and encourage him, but I am solitary and abhorred. 15
The monster wants to understand
"I am malicious because I am miserable. Am I not shunned and hated by all mankind? You, my creator, would tear me to pieces and triumph; remember that, and tell me why I should pity man more than he pities me?" chapt 16
The monster isolates himself and begins to question his existence. "Who am i?", "Where do I go?", "what is my destiny?". These are all questions that leave the monster in agony, that soon turned to hate.
I was dependent on none and related to none. The path of my departure was free, and there was none to lament my annihilation. My person was hideous and my stature gigantic. What did this mean? Who was I? What was I? Whence did I come? What was my destination? These questions continually recurred, but I was unable to solve them. (15.5)
The "monster" has looked for himself and firstly decides to be good, he feels the humans will see the inner him through good deeds and being kind, but unfortunately even after saving a life he is rejected. The monster vows to make the humans hurt just as much as he does.
The feelings of kindness and gentleness which I had entertained but a few moments before gave place to hellish rage and gnashing of teeth. Inflamed by pain, I vowed eternal hatred and vengeance to all mankind. But the agony of my wound overcame me; my pulses paused, and I fainted." (16.19-20)