Laws of UX · Experience and trust
Flow
The mental state in which a person performing some activity is fully immersed in a feeling of energized focus, full involvement, and enjoyment in the process of the activity.
The design-system take
Where the principle shows up in a token, component or pattern decision.
Interfaces that are too easy bore, too hard frustrate; clear feedback and progressive difficulty keep users in the channel. The best interface is the one you stop noticing.
Adapted from Flow on Laws of UX — Jon Yablonski.