Takeaways: 1) "what’s marginal to one user might be core to another" 2) APIs can afford to have more marginal features than UIs because the complexity is larg

Takeaways: 1) "what’s marginal to one user might be core to another" 2) APIs can afford to have more marginal features than UIs because the complexity is largely hidden. Done right, there's more API documentation but the main interactions aren't affected or made more complex.