For me, my hardest class was always english. I didn't subscribe to the "it's a classic because everyone says it is and I must enjoy it because it's a classic" method of taking the course. In collage when it came time to review Hamlet I basically broke out into why I don't think Shakespeare was that great (w/ supporting facts and arguments). got an A, second best paper I've ever written.
Best was a 14 page essay (trimmed down from the rough draft's 21 to fit the 7-12 page limit) on the history of the Corvette, focusing on the engine.