In The Great Gatsby, why does Nick call Tom and Daisy "careless people"?

Nick
refers to Tom andas careless people because he's witnessed them ruin lives and simply disappear
by hiding behind their wealth. Throughout the course of the summer,witnessedmanipulateand carry
on an affair with his wife behind his back. Tom displayed a complete lack of sympathy for George
and was simply using him so that he could communicate with his wife on a regular basis.
Similarly, Nick witnessed Daisy carry on an affair withand play games with his heart. Once Daisy
learned that Gatsby was a bootlegger, she went back to Tom...