“How do we deliberately add more emotional qualities into the products we design?”. First i would recommend reading Donald Normans “Emotioanl Design”, this is a very easy read an a good introduciton to the subject. I don’t really belive in all of Mr. Normans views, and thing “the design of future things should be more interssting”. The other book i would recommend is Design and Emotion, from the 3rd 2002 design and emotion conferance. It may be 5 years old, but the book contains papers all based on emotional design. Split into subsections, which are

Generative tools,
Evauative Tools,
Emotive Effects of Visual Properties,
Emotive Effects of the Other Senses,
From Design to Emotion,
Affective Usabilty,
Attachment,
Product Character,
Theoretical and Ethical issues,
and
Emotion in Design.

There is a paper for just about everthing, and there are only 4 – 5 pages long. There website design an emotion .org Has many resources for free.

Emotional Design: Why We Love (or Hate) Everyday Things £4.20

Design and Emotion £48.67