HD:
I am approaching an early retirement (as yet unsuspected by the employer) and view the prospect with very mixed feelings. My experiences are very much those of yours, and I suspect a large number of our contemporaries.
The more positive aspects, in addition to those you mention, include working with some of the finest people one could ever hope to meet. True, there have been a few dodgy characters too, but I believe these may be fewer in number than in any "traditional" working environment.