THE DESIGN OF EVERYDAY THINGS and EMOTIONAL DESIGN are two publications in design realm with profound influences. Norman, as a psychologist, have did a lot of research in design psychology. For these two books, I recommend that you guys could read THE DESIGN OF EVERYDAY THINGS first and than for the EMOTIONAL DESIGN.
In THE DESIGN OF EVERYDAY THINGS, Norman talked about the relationship between physical world and user experience. Especially for industrial designer, what kind of physical shape and limitation should be applied based on what kind of environment is quite essential for making a production that is easy to use. Different shapes and frames supply different limitations which create diverse hints and clues for informing people how to interact with such productions. For example, a tap with a knob, which shows that you have to rotate it to open; a handle shows uplifting it to open; a horizontal stick on the door shows pushing it to open the door; a door with stick handle which one side is higher and the other side is lower shows which side the door spindle located.
In industrial era, people usually got hurt by using productions that are easy to produce wrong signals with ambiguity shapes. So it is quite important for every designer be aware of their responsibilities and the importance of complying with basic design principles. Design should be people oriented, this is the biggest difference between production and artworks.
Except the physical shape, designers have to consider their target users' cultural background as well, which is the fundamental for people to foster a specific need and experience. It is common for the same production got utter different market reaction in different cultural region. One of the most outstanding examples to illustrate this point is the sales status of XBOX productions in Western and Japan market. (Although, I know that the reasons for the failure performance is complicated, it is obvious that different needs derive from different culture cannot be ignored.)