As one who 'retired' at 50, I have no complaints about the last 20 years.
Busy enough, without being told what to do on a daily basis.
Sufficient intellectual stimulation to defer senility for a while.
Enough free time/cash to indulge my/our interests.
I think the biggest positive was having the freedom to choose what to do each day, juggling the mix of desires and essentials and ensuring the week's "To Do" list was completed in a timely manner ... and not having to worry too much if things slipped to right a bit. Although looking at this desk, awash with various pieces of paper and a fairly long "To Do", I may be slacking a bit - I shall have to speak to myself sternly.