Almost everything I've ever done has very rapidly become normal. It's the way human beings tend. "Adaptation", they call it. Once I lived with a heroin addict in a kitchen. Every morning he went out for the day to score, kissing me on the cheek, and I pulled the candlewick bedspread - gold - over the mattress opposite the cooker. I washed his used syringe in the sink, squirting out the blood left in the barrel, getting it nice and clean. It seemed ordinary at the time. It was. Somewhere out there, I understood, suburban housewives were dusting and polishing, making the beds, clearing the breakfast table, and I thought they were really weird. How could anyone live like that, I wondered. It takes no time at all to get used to whatever we are doing. Something to do with the amygdala complex in the medial temporal region of the brain, I believe. It's why cats lose interest in chasing a piece of string after a while. Some part of the amygdala stops firing, or starts, and the novelty becomes merely repetitive. Become a junkie's moll, a psychiatric inmate, a teacher trying to get the attention of a class of adolescents eight times a day, a parent, a writer - all of it, after a short while, is just what you happen to be doing. Habit, arguably, is more powerful than liking or hating your circumstances. You get used to everything in the end.
Jenny Diski, London Review of Books