Philosophy
Philosophy is the single most important thing to engage with. How can we choose how to live our lives without questioning established structures, opinions and values. We need to ask ourselves deeply, why am I really doing what I am doing. Is it because i want to? Is is it because it is expected of me?
Questioning ones reality, especially if you used to live many years in it, is a hard and uncomfortable process. Though in the end it will be themore rewarding. Nothing worth attaining has ever been easy.