The only thing in my life I've ever been able to lose myself completely within has been struggle.
When I push my physical limits that is the only time that uncertainty, regret, and unknowable yearnings ever go away. Fighting myself or fighting others is the only thing that makes me feel 100% immersed in the experience of life.
Buddhists speak of a realm in the afterlife where there is nothing but combat. People exist as six armed beasts that fight each other nonstop for an incomprehensible amount of time.
Perhaps that is where I came from...or where I am going.