Psychological Usability Heuristics (uxmag.com)

This is fascinating. Although "rules of thumb" for appealing and usable design are included, what is more interesting to me are points further down (both in the presentation and in the depths of perception) such as "Unconscious Processes" that have things like "the system uses food, sex, and danger messages to grab users' attention" and "the system matches the user's mental model". The mental model thing is so subtle and so universally applicable.