Retired 5.5 years ago. It's all good.
Used to sleep 5.5 hrs (alarm went off at 4:30am) and was always tired. Now sleep until 7-7:30 am (and wake up whenever I open my eyes). Everyone always comments on how well-rested and stress-free I appear.
I have a very unstructured life but I find that I am never bored. I read, spend a lot of time online, meet friends for lunch or dinner, have joined a bunch of meetup.com groups (going dining, hiking, kayaking, etc. with them).
I make time for exercise (walk 4 miles at least 3 times a week, etc.) so I simply feel much better than when I was working.
I travel fairly frequently, sometimes for a few days and sometimes for 3 weeks or more. I love the time flexibility that retirement affords.
One slight negative: a long-term (16+ years) relationship ended a few years into retirement, so I've had to rediscover life as a singleton. It was a bit lonely early-on, but I actually love spending time alone now.
omni