What is a dark pattern?

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.

Here is the list of various Types of dark patterns.

And here are some of the examples of it:

Question for you

In the spirit of Halloween, I want to know if you have ever been asked to create or have created something sinister as a dark pattern (by accident or on purpose)?

My experience

I'm surprised to say that, even though I have worked in the eCommerce business for 4 years, I've never been asked to create something that would trick the customer into signing up for something or buying something that didn't want. From my experience, good merchants will always work hard to earn and keep their customer's trust.