The phrase "foolish things" refers to actions, ideas, or behavior that are not sensible, wise, or logical. It means doing something silly, stupid, or impractical. Full definition
For the kids, it's not to do foolish things out of sheer rebellion, because your parents are out to help you and keep you from harm's way. (qwipster.net)
It's easy to critique what's being written here, people are writing very foolish things. (religion.blogs.cnn.com)
Don't keep trying it on your own, yelling at your dog, or buying an electric collar, or any other such foolish thing. (samthedogtrainer.com)