For most, the difference between good and bad web design is whether or not a site is aesthetically pleasing and easy to use.
That view ignores the darker side of design.
Just as there are unethical “black hat” tactics for making a site appear in search engine results, web designers have come up with practices designed to trick people into signing up for services and buying products that, under other circumstances, they wouldn’t.
Dark Patterns is a site dedicated to revealing these tricks and the sites that use them. Harry Brignull, one of the site’s creators, has put together a presentation detailing some of their sketchiest tactics. Not all the sites in this presentation still have their UI’s organised this way — Brignull’s data covers years — but at one time, they all did.