Design versus development process

When people learn design techniques, they feel excited by the possibilities. Then the messy realities of a real project descend on them. They can't fit the new design ideas with the technology they must use. Or they don't know when to let go of a particular design aspect in the interest of time and when to dig in their heels and find a clean solution. Developers can and do talk with each other abstractly about the application of design principles, but it is more natural to talk about how real things get done. So, although this is a design book, I'm going to barge right across that artificial boundary into process when I need to. This will help put design principles in context.

Eric Evans, "Preface", in Domain-Driven Design: Tackling Complexity in the Heart of Software, xxii.