Typography is always an easy hit, so we're continually reading about this rule or that. Sooner or later the uninitiated will begin to assert some of these techniques just for the sake of the technique. Kerning, for example, was highly popularized with some of the early DTP programs. Suddenly every headline and title was kerned. Although that's OK when done properly, and in good taste, kerning for the sake of kerning usually turns out to be obvious to the reader.
People read to gather information.
Anything that stands in the way of this process is wrong. The communication process must be the sole purpose of any inventiveness. All creativity and imagination should be applied strictly to the service of these goals. You should always select a typeface that speaks to the audience in a tone that best reflects the subject matter without sacrificing readability. Your type combination will usually work when you establish and maintain a type hierarchy.