Dark patterns are intentionally deceptive user interfaces used by websites and apps to trick users into making unintended choices that benefit the company. They take advantage of users' tendencies to skim read and make assumptions. Common dark patterns include hiding extra costs until checkout, using confusing wording to pre-check opt-in boxes, and disguising mandatory actions or options to install apps without a clear cancellation option. The goal of dark patterns is to manipulate users for the company's financial gain through hidden fees, subscriptions, or data collection.