Quote 1
Another circumstance strengthened and confirmed these feelings. Soon after my arrival in the hovel I discovered some papers in the pocket of the dress which I had taken from your laboratory. At first I had neglected them, but now that I was able to decipher the characters in which they were written, I began to study them with diligence. It was your journal of the four months that preceded my creation. You minutely described in these papers every step you took in the progress of your work; this history was mingled with accounts of domestic occurrences. You doubtless recollect these papers. Here they are. Everything is related in them which bears reference to my accursed origin; the whole detail of that series of disgusting circumstances which produced it is set in view; the minutest description of my odious and loathsome person is given, in language which painted your own horrors and rendered mine indelible. I sickened as I read. `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. (15.8)
The monster, on discovering that his own creator is horrified by his existence, increasingly despairs about his position in the world. He faces the tragedy of his existence – that he was made human on the inside, but without the capacity for fellowship with others
Quote 2
"Cursed, cursed creator! Why did I live? Why, in that instant, did I not extinguish the spark of existence which you had so wantonly bestowed? I know not; despair had not yet taken possession of me; my feelings were those of rage and revenge. I could with pleasure have destroyed the cottage and its inhabitants and have glutted myself with their shrieks and misery." (16.1)
So, fun fact: in 1798, this guy Thomas Malthus warned people that overpopulation was going to destroy the planet, and that one solution was to get people (especially poor people) to stop having so many babies through family planning which, in the early nineteenth century, meant "stop having sex." Guess who wasn't a fan? William Godwin, Mary Shelley's dad, who thought that we could all just get along if we'd just try harder. (A lot of the Big Six felt this way, too.) What did Mary Shelley think? We're not sure. But that phrase "the spark of existence which you had so wantonly bestowed" sounds a lot like a condemnation of people having babies willy-nilly—especially considering that "wanton" is a word used a lot for excessive sexual activity, which, before our own age of family planning, tended to mean excessive babies.
Quote 3
"You are in the wrong," replied the fiend; "and instead of threatening, I am content to reason with you. 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? You would not call it murder if you could precipitate me into one of those ice-rifts and destroy my frame, the work of your own hands. Shall I respect man when he condemns me? Let him live with me in the interchange of kindness, and instead of injury I would bestow every benefit upon him with tears of gratitude at his acceptance. But that cannot be; the human senses are insurmountable barriers to our union. Yet mine shall not be the submission of abject slavery. I will revenge my injuries; if I cannot inspire love, I will cause fear, and chiefly towards you my archenemy, because my creator, do I swear inextinguishable hatred. Have a care; I will work at your destruction, nor finish until I desolate your heart, so that you shall curse the hour of your birth." (17.5)
The monster believes that a female companion is his only chance for happiness.