If you have a bad experience with an app then tell the developer what went wrong and how it could be better.
Waste your money?? I know people don’t want to pay for apps. You’ll probably pay more for a cup of coffee you drink once. Do you know how much a MacBook, iPhone, or Developer membership costs? Do you know how much time and effort went into making that app?
Try to offer some explanation or reason for your review. Constructive feedback will help make it better.
Make a developer happy and offer more info about how to make it better and fit into everyday life.