Brains make systematic errors of judgment, known as cognitive biases.
Cognitive biases are important for conversion. You want them on your side. Because your visitors unwittingly use them when deciding whether to buy or not.
Wikipedia’s list of cognitive biases is great, but Buster Benson from Slack got frustrated at its messiness—so he classified all of the biases, making them easier to understand and learn. His summary page is an amazing way to get them into your head (not that they aren’t in your head already, in a different form).
Once you have read Buster’s page, and you understand what each bias is, you may find the following awesome diagram—created by John Manoogian III—useful as a way of remembering them all. (You can click on the diagram to enlarge it.) You can buy a poster of it here.