The primary thing when you take a sword in your hands is your intention to cut the enemy, whatever the means. Whenever you parry, hit, spring, strike or touch the enemy’s cutting sword, you must cut the enemy in the same movement. It is essential to attain this. If you think only of hitting, springing, striking or touching the enemy, you will not be able actually to cut him.
The McNamara fallacy, named for Robert McNamara, the US Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations (or metrics) and ignoring all others. The reason given is often that these other observations cannot be proven.
The fallacy refers to McNamara's belief as to what led the United States to defeat in the Vietnam War—specifically, his quantification of success in the war (e.g., in terms of enemy body count), ignoring other variables.
We simply can no longer design and develop only for “optimal” content or browsing conditions. Instead, we must embrace the inherent flexibility and unpredictability of the web, and build resilient components. Static mockups cannot cater to every scenario, so many design decisions fall to developers at build time. Like it or not, if you’re a UI developer, you are a designer — even if you don’t consider yourself one!
...Sometimes interpreting a design means asking the designer to further elaborate on their ideas (or even re-evaluate them). Other times, it means making design decisions on the fly or making recommendations based on our knowledge and experience.