What you are describing is explained beautifully in "The Tyranny of the Marginal User" essay that got a lot of commentary on HN previously, https://news.ycombinator.com/item?id=37509507.
My favorite quote ("Marl" is the hypothetical name for the marginal user):
> Marl’s tolerance for user interface complexity is zero. As far as you can tell he only has one working thumb, and the only thing that thumb can do is flick upwards in a repetitive, zombielike scrolling motion.
My favorite quote ("Marl" is the hypothetical name for the marginal user):
> Marl’s tolerance for user interface complexity is zero. As far as you can tell he only has one working thumb, and the only thing that thumb can do is flick upwards in a repetitive, zombielike scrolling motion.