Cognitive load is the mental effort users spend to perceive, understand, decide, and act within an interface, drawn from a working memory that holds roughly 4 chunks. The design task is allocation: spend that scarce budget on the user’s goal, cut everything else, and mind the new debts run up by open loops and Slow AI. 26 design guidelines show how.

People judge a past experience by its most intense moment and its final moment, largely ignoring duration and the average of everything else. Fix your journey’s worst moment, build 1 genuine high point, and never let an error be the last thing users see: memories, not experiences, drive repeat business and word of mouth.