It works both ways. Sometimes I want to throw ideas around with a partner and other times I want to go deep inside an intuitive thought process. The key is to recognize what wants to happen at any given moment, and to have a culture that respects that flow. It really bugs me when people try to impose a predefined process on that. But it also bugs me when people come up with reasons to say co-programming isn't productive, when experience shows that it clearly often is. (Not that you were doing either of these things.)