I think there is a kind of grief associated with growing up that people don’t talk about. When you are young and inspired it seems like life is long and you can do anything, branching paths with unlimited doors. Once you're an adult, your past choices narrow down your future paths, and your sense of age starts to set in. In some way you mourn the paths not taken. This is called mortality, and can be a nasty combo with other depressive factors.

As you get older, you realize some doors not yet stepped through are now closed, and less doors are opened by others for you. Life can start to feel like a hallway with the investable at the end. While less doors are open now, life is still very free. You may now be able to see decades into your past, but you still cannot see into your future. There are many open doors still hidden, they just take a bit more searching. Good news, you are an adult with years of life experience, you can go find them.