However well-designed your user interface may be, at some point or other, the people using it are going to have to wait for something to load. Photo: Marco Giumelli, “Waiting” A 2014 MIT study showed that humans can perceive discrete images in as little as 13 milliseconds however deciding where to focus takes between 100 and 140 milliseconds. In practical terms, this gives us around 200 milliseconds to present a user interface state change in order to appear instant. Between…