As Jon Kolko notes in Thoughts on Interaction Design, interactions between products and people are like relationships in real life. Relationships in real life are emergent and not prescriptive.
How can we create products that can be shaped by their user and also shape themselves. What’s a new version of the Preferences window? Maybe a counseling session?
Also, digital apps have the unfortunate side effect of being ‘always new’. How can the wear and tear of a car or a loved coffee mug exist for web apps? (Maybe it can’t until we get to a bridging of physical and digital things).