Tons of folks love to use justified paragraphs in their documents. I personally prefer the ragged edge to my paragraphs, but to each his own!
Justified paragraphs align both the left and right edges of your text in your paragraph, as in magazines and books.
If you are one of the folks who uses justified paragraphs, you may have noted that when you add a manual line break in your justified paragraph, Word will force the line to the full width of your paragraph which looks very weird.
You can avoid this behavior by making certain that you enter a tab character just prior to your manual line break. When you do that, Word will make the line with the tab left aligned, and ignore the justification alignment you have applied to your whole paragraph!