Four years as a stockbroker formulated my primary objective in life: to grow old without becoming bitter.
I heard so many stories from bitter retirees who should have been enjoying comfortable retirements, thanks to the wealth they had accumulated: missed opportunities, lousy jobs, lousy bosses, ungrateful kids, etc. They spent too much time dwelling on the past.
As to my ungrateful kids, I simply say "you're going to miss me when I'm gone." lol
I’ve found that life is a whole lot less aggravating ones I learned to let things roll off my back.