To answer the OP and not talk about my situation, far too many people, at an age when they can retire, have zero ideas what they will do. Often far to busy earning a living/furthering their careers.
If you're on this forum you've already got a head start. Planning and getting ready to retire needs some idea of what hobbies, pastimes, sport, learning, volunteering you can and would like to do when you have a lot more free time.
It's boredom that kills newly retired folk who find the days are endless and have no purpose.
My FIL was a perfect example, never did anything other than work and watch TV.