以下摘自《Clean Code》，我认为这是本书最核心的部分，解释了为什么要写clean code。 如果你是一个码农并且还没有看过这本书，赶紧去买一本。
Bob enters the module.
He scrolls down to the function needing change.
He pauses, considering his options.
Oh, he's scrolling up to the top of the module to check the initialization of a variable.
Now he scrolls back down and begins to type.
Ooops, he's erasing what he typed!
He types it again.
He erases it again!
He types half of something else but then erases that!
He scrolls down to another function that calls the function he's changing to see how it is called.
He scrolls back up and types the same code he just erased.
He pauses.
He erases that code again!
He pops up another window and looks at a subclass. Is that function overridden?
. . . . . .
You get the drift. Indeed, the ratio of time spent reading vs. writing is well over 10:1. We are constantly reading old code as part of the effort to write new code.
Because this ratio is so high, we want the reading of code to be easy, even if it makes the writing harder. Of course there's no way to write code without reading it, so making it easy to read actually makes it easier to write.
There is no escape from this logic. You cannot write code if you cannot read the surrounding code. The code you are trying to write today will be hard or easy to write depending on how hard or easy the surrounding code is to read. So if you want to go fast, if you want to get done quickly, if you want your code to be easy to write, make it easy to read.