> Trying to retrofit an abstraction to a piece of code is almost always a horrible experience frought with mess and compromise. It is amazing to me that our ex

> Trying to retrofit an abstraction to a piece of code is almost always a horrible experience frought with mess and compromise. It is amazing to me that our experiences are so different: I have found the exact opposite of this statement to be true. The only way that I've ever come up with a good abstraction is by starting with something concrete (preferably two or more instances) and factoring out the commonality. Retrofitting a piece of code to an abstraction that was designed in a vacuum tends to be an exercise in frustration, due to the abstraction being shortsighted and insufficiently suited to the problem space.