



Your brain is essentially a future simulation machine.
The brain can be split into 3 main chunks (I'm simplifying): the hindbrain, responsible for many instincts; the midbrain, responsible for many emotions and sensory integration; and the forebrain, newest and best at future planning.
The forebrain takes longest to develop. It tends to be in teenage development that people have their first epiphanies about existence and their place in the universe. This hits emotional triggers very hard, and is written into your memory as an important experience, to make sure you remember it. Why? The theory is a sense of purpose and value of your life has survival value. You're more likely to live with a strong ability to predict the future, and "purpose" is very much tied to future planning.
Crises can happen when you lose that feeling of euphoria tied to future planning. And since it was tagged in your brain as super important, you feel a sense of loss that is very strong.





