Chapter #60. If You Must Use "Flat Design" then Add Some Visual Affordances to Controls
Minimalism is generally good and reducing clutter and visual distractions can often help a user to find what he or she needs more quickly. Minimalism does not, however, mean making controls so minimal that they are impossible to use.
The flat design aesthetic (refer to #7, Make Your Buttons Look Like Buttons) tends to remove visual affordances, but not to the same extent as the newly-emerging "web brutalism." Brutalism, inspired by the brutalist architectural style, is an aesthetic in product design that deliberately looks unstyled and raw (Craigslist is a great example).
Outside of being a joke for designers, this level of minimalism is too imposing and unnecessary and, like flat design, can degrade discoverability by removing all visual affordances.
Let's look at some UI in the widely-used Google Calendar (iOS) app. The strict adherence to flat design here means that it's very hard to work out what is...