Preventing Apps from Loading Recently Opened Documents (Mac OS X)

Problem: When you launch apps (such as Preview) on your Mac, the most recently opened documents are automatically loaded.

Solution: Go to System Preferences > General and check the "Close windows when quitting an application" item in Mavericks (OS X 10.9) or uncheck the "Restore windows when quitting and re-opening apps" item if you are running Lion (OS X 10.8).