"Everything happens for a reason." I guess this is technically true, if the reason is defined as "because people felt like making that happen." The belief that everything that occurs is to contribute to some positive ending is ridiculous. It's easier to believe that everything happens for an eventual negative reason.
"God never gives you more than you can handle." I think people who get run over and killed by trucks get more than they can handle.
"Karma will take care of it." The belief that you don't need to do anything to stop bad things from continuing to happen because a Final Destination-type invisible force will do it for you is just lazy.