Square versus round is a common theme in home decorating. It is sort of a basic philosophical point, an innate choice of style that everyone makes in a relatively visceral way. When choosing drink coasters, the conflict crystallizes, making the stylistic preference readily apparent.
There is a long and varied history of round against straight edges in the world of art and architecture. In general squared off right angles are easier to make. That’s why the simplest house will usually be a square or a rectangle. On the other hand, sometimes round is stronger, such as when constructing a dome, or an arch. In this way the rounded shapes have always been a little more advanced than the square ones.
In the Modern movement of art and design this idea was rejected, and square angular shapes began to be emphasized over what would have previously been considered sleeker rounded shapes.
However this is a thought process that has been turned back and forth a thousand times across the generations. It can actually be understood on an even deep, more symbolic level. Some people prefer straight lines and simple forms. These are often numbers people, people who try to understand the world in very direct and logical ways.
On the other hand you have squiggle people. They tend to be a bit more chaotic, they float from idea to idea, making connections in a more random, free way of thinking.
Of course, just because you are a squiggle person doesn’t mean you will prefer circular coasters. You may seek balance to your personality through design of the world around you.
You can also use design to balance out your day to day life. If you have a boring, exacting job, as many people do, that requires you to do the same thing over and over, you can balance this out with the art in your life. Seeking abstract images, and random chaos, can be healthy for your mind and your personality.
The question of whether to choose a round or a square drink coaster is one which stretches much further, and delves much deeper than a simple stylistic preference. It is a question of the way your mind works, the way you view and perceive the world.