The House Effect
It's probably unfair to call this the "House effect" because this problem predates that show by a few decades, but I'm going to anyway.
House effect: obsession (of both teacher and student) to know (in detail) the aspects of a disease that you should never see in your entire life.
I learn that 95% of all tumors of the gallbladder are adenocarcinomas. Ok, I'm fine with that. What I'm not fine with is a page of notes then devoted to the minutiae of that remaining 5%. It's not necessary. It wasn't necessary after I learned that 90-95% of lobar pneumonias are caused by strep. pneumoniae, and it isn't necessary after I learn that 98% of all peptic ulcers occur in the antrum of the stomach and in the duodenum. You can keep your 2%; I don't want to know it.
Under the same logic, I should NEVER HAVE TO KNOW ABOUT ANTHRAX. I'm staring at two pages of Anthrax notes right now, and while I feel very prepared to hold my own against a talking head on FOX NEWS, I sure as hell know that I will never put this information to clinical use. And let's say, for argument's sake, that I did? Let's say ten years from now I see a case of anthrax: I'm calling the CDC and letting them cough up their lung (which is what everyone should do, regardless).
The logic of the last 5% is pretty simple: if you treat 100 patients you'll see it 5 times, so you need to know it. I understand and respect this. I also understand that all the truly useful things I ever learn will be on-the-job. So if during rotations my Resident decides that I really need to know the 5%, then I'll know it. But just imagine how much more useful it would be if every medical student walked out of the first two years knowing 1) the top five causes of everything or 2) the causes that cover 95% of cases. Instead, I feel like I lose sight of the forest because the people writing my tests think the ant on that piece of bark on that rare tree is too interesting to skip. So I should probably know that instead.