I wouldn't know where to begin with the differences I found when I transfered to a rich american high school from a crappy french suburb equivalent.. Cultural differences aside, it felt like I was taken three years back, academicaly. There was no rigour, competition was there but tiny and less personal.
"Extra credit", "will that be on the test?", "make-up work", lax deadlines, non-linear grading...
It was too easy. I passed almost all my tests knowing 5min after walking out what few questions I missed and what the right answers were.. I'd follow in class, but my finals studying was basicaly one or two hours spent reading from books and notes at the test class' doorstep.
The very frank way to say it is that most of the kids there were too spoiled to care. There were a few very good teachers that knew their stuff, but unfortunately they were too few to make enough of a difference.
Most kids would have known better if they'd spent some time abroad, though.
And I skipped the graduation thing to go see my GF graduate instead, but would have skipped it anyway.