In my college calculus class (honors), we started from very basic principles. For the first one or two homework assignments we had to do things like prove that -(-a) = a. So, when I sat down to my homework, I carefully divided the paper into two columns and proceeded as I had in my high school geometry class. (Proofs of such "obvious" facts actually seem easier to do by such a rigid method.)
Needless to say, the poor grader/TA was beside himself when he saw this! He was fresh out of grad. school and had never seen a two column proof in his life.