Clarity and Design
Explaining a difficult topic or concept with 100s of pages of dissertation is easy. When you have no limit to the amount of words you can use or analogies at your disposal, you can keep writing or talking until something sticks. The challenge comes when you need to convey a complicated idea in a minimal amount of words.
It's for these reasons that good design is such a difficult task. Look at iconic logos and slogans, they seem simple at first glance, but probably took weeks to land. Conveying a brand or company vision in a single line of text is no small feat.
The best design and marketing will always seem like it is an obvious fit, that it couldn't be any other way. We recognize it by proclaiming the beauty in its functionality and simplicity. But never mistake clarity and simplicity with ease of creation.