I’ve been making a man with blond hair and a tan, and he’s good for relieving my tension.
Frank is the parody version of Dr. Frankenstein: a mad scientist who goes beyond the morality and conventional limits and puts life and death in his hands while creating life out of death. Frank’s lab is on top of his castle in contrast to Dr. Frankenstein because he doesn’t feel the need to hide. He is also open in his personal and perverse intentions in creating his version of the monster for own pleasure.
There’s a light, light in the darkness of everybody’s life.
Brad and Janet are somewhat reluctant by the appearance of the castle and its occupants, but this line shows that they are open-minded (somewhat naïve) people who are ready to put their trust in anyone and hoping to find light (goodness) everywhere. As the movie progresses, Janet and Brad become more accustomed to the castle and the weird people there, even going through transformations themselves to become a part of them.
He never liked me!
One of Riff Raff’s final lines in the movie before killing Frank shows that he, as many of the others in the castle, wanted to be liked/loved by Frank. Frank doesn’t love anyone but himself and uses the people for his own advantage and pleasure, even humiliating Riff Raff by whipping him. But, this still doesn't stop those around him to be enchanted by him and wanting his attention. It is clear that Riff Raff’s anger and contempt is partially due to this lack of love.