Choosing the wrong font, however, can be jarring to the eye and cause your brain to get confused. Just think of the brain teasers where the word RED isn't, and YELLOW makes you see BLUE.
Are you confused yet? That is exactly what a poor choice of fonts will do. A common mistake is to use too many fonts in a document. Just because you have the ability to install 150 fonts on your desktop, it doesn't mean you should be tempted to show everyone all the fonts you have. It interrupts the flow for the reader, sometimes making your audience have to go back and read something a second time.
Another common mistake is to use a font that is very ornate. If the audience cannot distinguish a "t" from an "f", your message is lost. Again, what is the story you want to tell?
A very basic rule of thumb is to use one font in your headlines and another font in your body copy. There is some wiggle room, but it is a good starting point. In typography, less really is more.
Future blogs will talk about how illustrations and fonts can work well together, once you understand the chemistry between the two.