Cooperation has a transactional nature, we agree it is a mutual good. Collaboration is deeper, we don’t know what the transaction is, or if there is … - Ward Cunningham

All the time we find ourselves in situations where people know things about the program, but they can't apply that knowledge to the program. Why? Because the knowledge runs counter to some organizational decision that was made before they had that knowledge. In other words, the program becomes resistant to that collection of knowledge.

There is an art to knowing where things should be checked and making sure that the program fails fast if you make a mistake. That kind of choosing is part of the art of simplification.

There's been an awful lot of discussion about what is or isn't simple, and people have gotten a pretty sophisticated notion of simplicity, but I'm not sure it has helped.