In a nutshell: how Cocoa and Objective-C code should look
Once you've figured out the basics of Objective-C and Cocoa, you're ready to start writing some code. But the conventions of naming and formatting Objective-C code are not the same as traditional C, C++ or even Java programs.
Apple has laid out a set of guidelines as to how code should be written for maximum clarity and integration with the frameworks. In addition, there are some undocumented conventions that Cocoa developers often use.
In essence, the human factor present in Apple's products for the end user can be found in Objective-C and Cocoa themselves.