Are plastic bags such a good idea? We don't think so. Plastic bags are bad for the environment because when you throw away a plastic bag, you can't reuse it and it fills up the landfills with pollution that is not good for the air. So to save the environment, use reusable bags. Think about what you put your lunch in when you bring it to school. Think about it when you stop at a store. We think a reusable bag is the way to go and you will help everyone.