Being retired is pretty darned good; I don't miss work one bit.
I would suggest gardening as a post retirement activity. The weather, weeds and bugs don't care at all how important you were or thought you were. They'll try to destroy your crop all the same. And when you've finally coaxed that perfectly ripe, beautiful and delicious heirloom tomato from the the plant to your plate, you'll have a satisfaction that no job can give you. We have a plot at the community garden. Most of the other gardeners are also retirees. I could not tell you what a single one of them did for work, and they don't know what I did. We talk about what we've planted, how it's growing, what might help with the pests, how we are coping with the weather, what we might try next year and such. Just a bunch of people who enjoy a wholesome activity out in the sunshine and fresh air.