Comparison of hyphens, minus sign, dashes, and underscore.
Here's a nice paean in the NYT by Ben Yagoda to one of my favorite punctuation marks - the dash. I admit to overusing it a bit, but sometimes it's the best way to reconcile disjointed thoughts or to emphasize a point without being exclamatory. Dashes can make the difference between a heartfelt statement versus a bland one. In his essay, Yagoda provides examples of quotes using dashes by famous authors, which could have been written with commas or semi-colons, but would lose a lot of feeling. The dashes elevate thoughts to loftier heights! He asserts that Emily Dickinson was the "Nobel Laureate" of this punctuation, though other writers such as Mark Twain, Henry James, and F. Scott Fitzgerald were also proponents. In reading more about the dash, I've learned that there are different kinds of dashes and these must not be confused with hyphens or the minus sign, which look and function differently. The most commonly used are the en and em dashes. The various dashes and their sizes and uses are described very thoroughly on Wikipedia. The em dash is often used to denote a break in thought - something I'm often known to do. It just feels right to break up sentences in this manner, so as to provide an aside or a bit of drama in exposition. So, try a dash sometimes - it's the right thing to do!