I watched my dad fall into depression after retirement. The same for a family friend who was able to retire early in their 40's. I think a lot of people only plan for the financial side of retirement and don't plan for post-retirement hobbies and activities. It took these 2 people's examples to open my eyes a bit and start planning for a heavy hobbying which will also look different from light hobbying where you are still committed to other things like work and raising a family.