What I've discovered is that the further you go past 40, the more you start to develop the "Murtaugh list" ("Lethal Weapon" reference -- "I'm getting too old for this $#!+"). Kind of a companion to the "bucket list." For me it tends to come down to certain people and relationships -- life's too short to let Xxx make mine stressful, or, to run myself ragged helping run a certain convention with nothing to show for it and more complaints than compliments.