Universality is in the core of the World Wide Web, so we should embrace it and build systems that are available to, and accessible by, everyone.
Consistency enhances clarity and makes our system more predictable and efficient to use. Users shouldn’t have to wonder whether different actions or terminology used mean the same thing.
Good performance is good user experience. We should strive towards making our system as fast as possible in terms of both network footprint and the time it takes to become interactive.
Modularity reduces complexity and improves our system’s reusability by breaking it into small, easy to consume parts.