I got a C in Calculus 3, the class was structured such that I could just guess and complete the assignments well, but I didn't learn any of the content necessary for the midterm or final. I nearly failed Statistics because I wrote a Common Lisp package instead of using Excel and the professor thought I was being a smart ass or something so decided to not grade my final until a combination of vague threats and apologies were made. Analysis I, II, Probability Theory, etc. no problem though.