The principal character in Joseph Heller’s famous World War II book, Catch 22, is Yossarian. In it there is an apocryphal incident which illustrates the need to make sure you tackle the right problem.
During a combat mission which Yossarian is flying, his plane takes heavy anti-aircraft fire. One of his colleagues, Snowden, is wounded. Yossarian sees that he has a leg wound and puts into action his first aid training and treats it with bandages and sulphanilamide. He makes a great job of it and feels very pleased with himself.
To comfort his colleague, Yossarian undoes the top button of his flying suit. As he does so a massive wound is exposed and Snowden’s internal organs spill out onto the floor of the plane. A huge chunk of flak had ripped straight through his ribs from behind. Snowden is about to die. Yossarian covers Snowden in a parachute, and comforts him by saying, “there, there”. Snowden dies.
Moral of the story:
Make sure you check for all problems and focus on the critical ones.