Finder - you can "blindfold" the Finder by pressing the OPTION key when you change things on the desktop. Can be time saving - 1. You won't have to manually close all those folders you have opened.
2. You won't have to re-insert an ejected disk
(whose desktop you have changed). 3. When you rearrange your desktop, the changes are recorded, resulting in a delay before an application opens. The one time you can't blindfold the Finder is when you use it as a shortcut to close all windows.