The phrase "periodically reinventing myself" is really a good one. DH and I look at is as that we periodically reinvent our lives. When we transitioned to being full-time RVers after 5 years retired we were extremely conscious of the reinvention part, so most of our choices were very deliberate.
Realizing that retirement in not some permanent scenario in terms of what you do all day, but rather a fluid lifestyle where most of the choices are in your control, is pretty important. I think sometimes people feel anxious about retiring because they're afraid of getting bored or getting stuck somehow. Whereas if you try something and it doesn't ring your bell, then do something else! You can't figure this out ahead of time, so you have to be willing to experiment. There is no "end goal", so you have to focus on the process.
It may also be that we're used to someone else setting the priorities, establishing the daily schedule and so it's hard to imagine doing that yourself. And it does take more effort to control your own life, rather than having an organization call the shots.
Audrey