Windows: Some programs seem like they should come by default with Windows. FoldersPopup gives you one-click access to your favourite folders and locations.
It's a portable application so you won't need to install it. Unzip the folder, run the program and start using it. You can hit the middle-click of your mouse or Win+K as a keyboard shortcut, which will activate a context menu with favourite folders. The favourites are customisable (and, when you're in any folder, you can add it quickly to FoldersPopup), while there's a list of Special Folders such as Desktop, Recycle Bin and Network Places.
The cool part is that FoldersPopup works with a dialog box. So when you are prompted to save or open a file, hit the shortcut and you will get the option to save. It's brilliant, and it saves a lot of time. Supported dialog boxes are Export, Import, Open, Save, Select and Upload.
Note that FoldersPopup only works on your desktop, Explorer windows, and the aforementioned dialog boxes, so it doesn't override middle-clicking and Win+K as shortcuts in other applications.