Thanks everybody! Here's a handful of my own reasons--
To make it to middle age you had to survive fires, floods, heartbreaks, disappointments, griefs, elations, separations, frights, random wombat attacks, mistakes, compromises, and freckles. The end of the world, isn't.
You know nobody has a perfect life but you know what good feels like to you.
You've given out enough good advice that you can start to follow your own.
You've given out enough bad advice that you know what advice to ignore.
The negative voices inside your head have started to mumble and forget what they were talking about.
You no longer worry about getting to the destination on time. Getting there before it closes, with friends, and having enough left to buy a pint or two-- that's heaven enough.