According to Plato, we find things beautiful when we sense in them qualities we need, but are missing in our lives. In other words, beauty has a practical application.
This is why busy professionals from busy cities tend to like minimalist, often geometric living spaces. Their minds miss simplicity, hence…
People with less cluttered lives tend to surround themselves with more ornaments, textures and details. They're open to more stimulation, hence…
A similar causes and effect phenomenon is in play with flat design. When display technology first gave designers a full gamut of colors, we leaned towards skeuomorphism — a practice of making items represented resemble their real-world counterparts.
This helped users new to these personal technologies replace their 3D real-world tools with 2D digital ones. It was most beautiful, because it was most practical. So a camera app would make its icon look like a real camera. A calculator app would make its icon look like a real calculator.
Today, getting people comfortable with technology is no longer a big problem. In fact, solving this problem has created a whole new problem — information clutter; messages, notifications, feeds, listings etc.
Information needs to be refined into meaning for it to be useful. Technology is trying its best to do that. Ten years ago searching “what’s the weather” eventually landed you on to a weather website where you’d refine information to find what’s relevant to you. Today, you get the weather info specific to your location before you even finish typing the search query.
But easier weather updates is not enough. There is an incredibly high amount of other information we have to refine every day. It is only natural that our minds find beautiful they miss — quick, to-the-point simplicity. Icons and shapes that instantly tell us they mean, without requiring much processing.
Good flat design helps us think less. It gives us the minimum amount of visual information necessary while communicating the most amount of meaning quickly. It frees our minds for more complicated tasks. Our relatively recent lack of simplicity has led to its popularity. Like all trends, this will change with time.