The First Rule of UX
Basically, it’s the Circle of Life.
Any change to the tiniest of details, directly affects the rest of the elements and how the intended message will be communicated. So, by changing the tone, colour, weight or placement of an element, the designer can create an obstacle or facilitate a positive user experience.
Brewer says we should ask (and ask often) “Does this element support or contradict what I am trying to communicate to the user?”. And, by asking this, you will find yourself refining and improving the little things; the things that often go unsaid or unnoticed, that ultimately make up the user’s experience.