The Diary of Anaïs Nin, Volume 1: 1931-1934, by Anaïs Nin.
This book ate up most of my September and the beginning of my October mainly because I could not bring myself to pick it up at times. It gave me great one-liners to use as catalysts for writing prompts — gave me great paragraphs to cause an introspection or two — but it mostly made me realize how much I only enjoy my thoughts and no one else’s.