Contrast

Strong contrast attracts the eye and underlines the message being communicated. It's like the lime that goes with the tequila.

Unlike the previous examples, the words, "full of sound and fury" clearly stand out from the rest of the paragraph. The choice of typeface emphasizes the energy of the message.

There is a clear contrast between the header and the smaller text. Also note the difference in weight between the lines and the border.

This illustration uses two very different faces. The graphic was picked to go with the bold type face.