Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Confessional, Didactic
Rousseau doesn't have a problem outlining all of his flaws. He's pretty harsh on himself, actually: "Thus, before my future career was decided, I wasted the most precious period of my childhood in foolishness" (1.2.1). Ouch—Rousseau realizes that his tone needs to be confessional in order to keep his readers engaged and keep himself honest.
Why, exactly, is Rousseau putting it all out there? He wants his readers to benefit from his experience. Now, that doesn't mean that Rousseau thinks everyone should steer clear of his mistakes. Nope, Rousseau thinks that being totally honest with his readers will give them a glimpse into a hot mess of a human being.