Hi! I am a senior citizen, as is my wife. It's our fifty-fifth wedding anniversary today. So what activities do we currently participate in? (and there's been one helluva lot in recenty years)
Well, my wife is involved in voluntary work raising money for charity. She works anything from one to four half-days a week at this. Also, she organizes at lot of the social events for those who work with her as she's on the local group's committee.
For me, I'm into public speaking, storytelling and teaching my club members and others about this. I've been a Toastmaster for most of my adult life. I'm currently in four Toastmaster clubs. I also do a lot of Creative Writing, having written about ten books and around 400 essays since I 'retired' in 1995.
You could generalize and say that 'retirement' - provided one spends time doing the things one loves to do - is the most productive, rewarding, and joyful period of one's life, the proviso being that one is in good health.