Students see no reason to do well in school. In geography, to take the example that this thread is based around, we have a specific class for it, generally a sophomore class. Well, I'm currently in that class (I don't know why I didn't try to test out of it), and I can say that students don't bother to learn in that class. They can't draw maps. They can't label maps. They can't do anything with maps--some can't even read them! All those African countries? They're just names on an unreadable map, good only for the sake of laughing at how "funny" their names are. World leaders? Hah! That guy's middle name is "Bongo"! The best they do is make puns about it.
Heck, we had a question on our "Europe" test. Everyone said it was the hardest on there. Admittedly, it was, but some people didn't have a clue what to write for it at all. The question? "Describe the German culture, based on language, religion, etc." Yes, they didn't even know what religion it was; they could barely remember that German was the language.
On the same test, we had a former Yugoslavia question. Well, we spent three days on Yugoslavia, reviewing how each nation broke off. The question was which of four nations did not break off from Yugoslavia: Slovenia, Croatia, Macedonia, and Albania. They apparently couldn't remember all of those nations we talked about; a large number picked Macedonia or Slovenia.
Even the good students in the class learn only insofar as it will help them on the test. They study their maps hard the night before a map quiz, ace it, then they completely forget about it.
It's no wonder that our students come out of high school completely uneducated. There's no motivation for them to learn anything.