With insight into why people don’t read manuals and why features sell products:

http://www.codinghorror.com/blog/archives/001048.html

Also:

http://www.jnd.org/dn.mss/simplicity_is_highly.html

http://www.joelonsoftware.com/uibook/chapters/fog0000000062.html

From the Norman essay:

Logic and reason, I have to keep explaining, are wonderful virtues, but they are irrelevant in describing human behavior. Trying to prove a point through intelligent, reasonable argumentation is what I call the “engineer’s fallacy.” (Also, the “economist’s fallacy.”) We have to design for the way people really behave, not as engineers or economists would prefer them to behave.

I find myself re-learning this again and again.