Onur Cobanli explains:
When you think about it, one element that makes a good design great design is whether your design is able to communicate itself; for a design to communicate itself it should be easy to understand, easy to comprehend, easy to get used to, easy to use. In general, good design is easy to use; and great design is even easer to use; even easer to understand and even more easy to get accustomed to. Great design very well communicates the advantage created by good design; the advantage of good design is to function well; and great design communicates the idea that it will work well; that it is a great fit.