A 73-year-old man, with diabetes but in excellent health (he’d played professional sports when younger, still ran 5 miles a day), had vomiting and diarrhea for 5 days. He became dehydrated, and was seen at an urgent care clinic. They obtained lab tests (which got lost), gave him IV fluids, he felt better, they sent him home (his wife begged to have him hospitalized). The next day his symptoms continued. Frustrated, he refused to return, and died that night. His extreme vomiting and diarrhea were clearly due to some serious disease (e.g. Sepsis, etc.).
So the clinic treated him well, but never made a diagnosis. Nobody knows what he really had. The key point that escaped them, is that there’s no simple virus that causes 5 days of vomiting & diarrhea without beginning to get better. So they’d focused on the dehydration, without asking themselves, “What’s the germ?” (or other possible cause).
Clinicians often get swept away by, “What can I do?” Much more important than “doing” (treating), is figuring out what’s going on. Diagnosing!