In design (UIs, pricing, etc.), there is a constant battle for attention & processing between emotional and cognitive. Round numbers and solid icons are underst

In design (UIs, pricing, etc.), there is a constant battle for attention & processing between emotional and cognitive. Round numbers and solid icons are understood and don't set off mental red flags. When things become more difficult to understand, we either assume (correctly or incorrectly) or have no choice but to make an effort to fight those expectations. On reddit, there are popular subreddits like /r/oddlysatisfying, /r/mildlyinfuriating, and /r/mildlyinteresting that demonstrate intrinsic attraction and repulsion to said expectations. In the world of interface design, there's been some debate regarding solid vs hollow icons in terms of processing. Here's a well researched article that sheds some light: http://viget.com/inspire/are-hollow-icons-really-harder-to-recognize-a-research-study http://viget.com/inspire/are-hollow-icons-really-harder-to-r...