I think retirement is a bigger adjustment than most of us give it credit for, and one for which we get virtually no preparation, unlike much of adult life.
Almost from birth we are "preparing" for adult life; we have to go to school and learn all this stuff, much of which has little to do with what we end up doing, but we don't know ahead of time what's going to be useful and what isn't. Then you reach early adulthood and either go to college (more learning "stuff") or go in the military (you'll learn a thing or two there also) or actually get a job that you think might be useful and interesting. Or maybe you just thrash around for a bit until you discover who and what you want to be. If you're lucky anyway; some people never make that discovery.
Time goes on and money and circumstances allow you to retire and sit on your butt for the rest of your life if you want to, but you've been conditioned all your life that you "must" do this and that to "prepare" for the next phase of life. But there's no preparation class for retirement.
You'll have to figure that one out on your own because everyone is different. Some figure that "I gave at the office" and it's okay to sit in front of whatever screen entertains them with a beverage of choice and in truth that is okay; there's certainly no law against it. Most of us would be pretty bored with that rather quickly though. And therein lies the problem; what do you want to do within the constraints of time, money, and (inevitably) physical ability?
I just remembered. Quite a while back, in 2009, member Nords wrote a wonderful piece on this subject titled "
The Fog of Work". I think it's worthwhile reading for anyone considering this subject.