You can use the tab key to autocomplete any path in the Finder Go To Folder window (Command+Shift+G).

To try it out, open the Go To Folder window and start typing the path to a folder, like ~/Library/Pre then hit the tab key to complete the rest of “Pre” with “Preferences” – this is extremely useful when you are accessing lengthy paths in your filesystem.

Auto-completion should be familiar to anyone with a unix background, since it is regularly used within the command line interface.