Quick update on turning Five-O: It's not going too well. I have ten days to go, and introspection and fear are the order of my days. Shirley said it was worse before she turned 50, and afterward it was no big deal. I hope that's true.
It's really unfortunate that this is such a time of change for the world, it exacerbates the feeling that it is a time of change for me. Ever since my Midway experience, I've thought of turning 50 as an inflection point. Naturally I'd like to think it will be upward, but all the external evidence suggests otherwise. Fifty is just a number, so clearly any effect turning fifty would have is pschological, but it is definitely having an effect.
If you have not turned fifty, I recommend you put it off as long as possible :)