Lines in word processors have a finite length, but entering a space or a hyphen can sometimes separate words you'd rather keep together. Ctrl+Shift+Space and Ctrl+Shift+- can fix this.
In the example in the image above in WordPad, entering a regular hyphen between "Shift" and "Space" would result in the first two words remaining on the first line, while "Space" would be placed on the second line. By using Ctrl+Shift+- to enter the hyphen instead, all the words are kept together and placed on the next line, which looks a little better. The same rules apply for spaces.
It's a small distinction, but if you're dealing with critical pieces of information that need to be kept together, presentation makes all the difference. It doesn't work everywhere, but it should work in most major word processors.