Water flows through a system by taking the path of least resistance. Or at least, by having more water go through the low friction paths, and less water through the high friction. It’s the same for people walking through a stadium, or your energy when you go through a day of work.
Friction isn’t the thing itself, it’s an attribute of the material of the thing and how it affects whatever is moving around it.
UX design is the science of studying this friction in the realm of the digital: minimize the number of necessary clicks. Minimize the time taken to complete a task. Amazon’s one-click checkout button.
But so much of the psychological can’t be measured directly. Take, for example, context switching. Or the emotion you feel about certain email subject lines. The cost of a single distraction when you’ve entered a state of deep work.
How much of human progress is held back by unnecessary friction? And who is doing some of the best work to minimize that friction?