I've experienced it - in fact I'm in the middle of it. After telling my boss I was going to leave after the end of the year to spend time time with my family, my employer came back with an offer of part-time work. They've promised to find a "job I'll love" come January and I'm hanging around long enough to find out if it is, in fact, something I'll love. If it's not, I'll be pulling the plug. If it is, I'll keep doing it awhile and see if I love that job more than I'd love doing something else.
One of the big things that gave me the courage to tell my boss I was leaving was the realization that I wasn't choosing between two distinct choices. I had created a false dichotomy between work and retirement. I was thinking about it being "all-in" for either path. I realized that I can leave my job and, if I want to, rejoin the working masses in a year or two. I can choose to work part-time for money or for that matter to just volunteer my time. If I do, it won't be because I need the money, it'll be because I want to do the work. I'd probably take a big pay cut but who cares, I'd be working because I wanted to.
Good luck with your decision!