If you are the kind of person you want to read what has been changed before updating an app you can disable the auto app update setting. Or enable if you want updates fully automated.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.
VirtualBox is a great free cross-platform virtualization program that enables you to run Windows, Linux, Mac OS X and other operating systems on you Windows, OS X or Linux computer.
Mac OS X Mountain Lion has 43 secret desktop wallpapers hidden in one of its folders. They are all beautiful, high quality and this is how you find them.
If you experience an Mac OS X program to freeze and you cannot exit it by clicking quit or using a keyboard shortcut, you can always force it to quit using the Activity Monitor.