"Although there are many times in life you’ll consciously decide to act in a certain way, this is the exception, not the norm."
IMO, that's the most important idea there. Your personality is what you've created to live among others like you, but as your personality grows, it develops habits that have weight and momentum, and later in life those habits start defining your actions completely, you get progressively smaller windows for true self expression, and your life starts feeling dull and mechanical.
Your attention is the only thing that's truly yours.