I finally - sort of - understood those people after reading David Keirsey's Please Understand Me II, a book about different personality types.
Some people really do believe that nothing they do will have any effect on their lives, and (from my perspective anyway) are willing to just put their lives in a bottle, throw it into the ocean, and hope they land on a nice beach instead of being smashed on the rocks. I have a good friend who believes that. He believes that "what will be, will be" and he doesn't concern himself with it.
He's 56, an aircraft mechanic and pilot, earns about $65K/year, has about $250K in an IRA and a Pitts Special airplane that he built, (worth about $90K) about $25K worth of tools, and those are his assets. He's not the least concerned. I think most of us on this board would be frantic.
On the plus side he has a frugal lifestyle - he rents his modest dwelling, buys his clothes at Goodwill, brown bags lunch, doesn't own a TV, and only last year bought a computer. So he's probably the kind of person who CAN live on SS and little savings and not feel deprived about it.