Deceptive design patterns (also known as "dark patterns") are tricks used in websites and apps that make you do things that you didn't mean to, like buying or signing up for something. When you use websites and apps, you don’t read every word on every page - you skim read and make assumptions. If a company wants to trick you into doing something, they can take advantage of this by making a page look like it is saying one thing when it is in fact saying another. You've seen them before: the UX ploys designed to trick you into spending money, or make it nearly impossible to unsubscribe.