At first you feel guilty. You SHOULD be working. Something feels unnatural. But soon, you're no longer governed by clocks or by money. You're just YOU! There is nothing to prove to anyone. You read, if you want to, you paint, if you want to. listen to music, if you want to. You have time to move at your own pace. You are at once, limitless, boundless, infinite. You're not resigning to old age. You can now become the real you.
Expand your mind. Indulge in your interests. Do whatever you want!
It can be scary to leave one identity for another, but it can also be invigorating once the new identity of a retiree takes hold.