I can't offer much in the 'life is worth living for because...' department.
All I know is that sooner or later something is going to catch up to us.
In the mean time, work on being a grouchy, crusty, curmudgeon. You'll develop a dry and acerbic sense of humor. Eventually, you'll find yourself laughing at yourself with the way a conversation goes, and ends with something like:
Friend: "Dude, what is your problem? I ought to kick your ass for being such a douche!"
You: "Too late dude, my body is already doing that to me."
----------
Friend: "Man, you seem to be coming apart at the seams."
You: "Tell me about it."
Go ahead and be bitter at the world, just try not to wallow around in it too much.
Holy crap dude - sounds like you are falling apart!
If you haven't checked out 'Arby n the Chief' in awhile, you missed out on a great season. The trailer for the new season was just released moments ago.
All in all, pretty damn good. I've worked my way through some RL hurdles and some things are coming back together quite nicely. If all goes well, I should be semi-retired in full (I'll never fully retire) within a year.
I just hope the economy doesn't go completely into the toilet in the mean time.