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The nearer I approached to your habitation, the more deeply did I feel the spirit of revenge enkindled in my heart. (16.17)
When you think about it, it totally sounds like the monster has a crush on Frankenstein: he even gets nervous and fired up when he closes in on the love/hate of his life.
"Frankenstein! you belong then to my enemy--to him towards whom I have sworn eternal revenge; you shall be my first victim." (16.30)
Notice that the monster thinks of William as "belonging" to Frankenstein. He doesn't seem to see much difference between killing William and burning down De Lacey's cottage—all's fair in revenge and war.
This was then the reward of my benevolence! I had saved a human being from destruction, and as a recompense I now writhed under the miserable pain of a wound which shattered the flesh and bone. 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. (16.20)
Although the monster is compassionate, he learns that others are not. The world is indifferent at best, and hateful and mistrusting at worst.