Television series, even good ones, tend to follow a set pattern. In this particular series we know that numerous logical but ultimately incorrect diagnoses will be raised, until it seems that even our brilliant diagnostician is going to lose his patient. But then a side remark, usually related to the sub-plot of the episode, causes a lightbulb to light up above his head and we know that he's figured things out and in the last remaining moments of the episode will succeed in saving the patient.

I have nothing against happy endings.