Examples:

1. What matters to us about the ground at our feet is that it is something on which to stand, walk, build, or grow rather than its colour, for example.

Insights:

1. We view things in the world by what they can provide us, rather than their actual qualities.
2. A product's affordance are what the users can achieve by using them.

References:

1. James J. Gibson: "The affordances of the environment are what it offers..., what it provides or furnishes, either for good or ill."