Once adulthood loses its novelty a lot of reality sets in. Life past 30 has a way of reducing and spreading out the waypoints of excitement that serve to re-fuel the soul. After life's obvious milestones: marriage, kids, buying a house, finishing a graduate degree, getting a job, etc. the world opens up for you in a way that can make you want to run away and hide from it.
There's a loss of romanticism that can make even the things you know you're lucky to do, and you are grateful for, seem like arduous tasks. This is how you lose an edge.