This book dives into people's automatic behaviors: the habits. I learnt a lot of things inside, including how habits really work, how habits are created and how habits can be changed.
That was a real insight for me because I discovered that habits were responsible for many of my previous successes in life, including how I learnt languages and how I unconsciously associated learning with gaming, something that always helped me to study quickly without even thinking I was studying.
I liked so much the book that I even did a video review:
You can get it here:The Power of Habit: Why We Do What We Do in Life and Business