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.
If something ships from one of the companies I advise, and it is virtually unusable because of poor design (which as we all know occasionally does happen), you can bet I go directly to the designer and ask how this happened? It is absolutely on the designer to ensure this does not happen, so something went wrong.
Similarly, if the product ships and performance is terrible you can bet I go directly to the tech lead with the same question.
And most frequently of all, if something ships and the analytics show that it’s either not being bought or not being used, or it turns out that it violates some business constraint like compliance or privacy, you can bet I go right to the product manager with that question.