I have just attended a lecture purely on why we love or hate everyday objects, some interesting comments where made and my eyes are truly wider after this one. Form function or simply just prescence.
Form is the obvious one but what forms do we warm to more often, studies show that curved soft floating forms, ideally the circle is the perfect form and the one that makes us warm and fuzzy inside will always refer to this basic principle.
Function is critical and all good design just works it performs it's duty seemlessly and hides all technical aspects, apple technologies is a beautiful example of this.
Product prescence and reputition is a human sub conscious way of warmer to something, through familiarity we feel most comfortable, like turning up to the same work place each and everyday we feel comfortable much like Bering in contact with familiar products or ways we interact with them draws us closer to them. Click the link above for further reading. Dh