Honors multivariable calculus and linear algebra. It was tough because it takes an incredible amount of work and then, if you're not smart enough, you STILL can't solve the proof.
People frequently say that mathematics is perfect. Unlike physics, it is built upon axioms defined by humans. These flawless axioms sets the rules for this world you travel in. It upholds the integrity of every line you write, and theorems compiled through history are simply little gems that helps you get to your destination. But traveling in this world is not simple because not everyone is gifted w/ foresight.
You're sitting in the library for 12 hours straight attempting to solve these ridiculously elaborate proofs that spans pages, you're getting close, and finally BAM! You're stuck on a step. You can't figure out the next piece of the puzzle. You are done, you are dead, you failed. You spend the next 3 hours trying different permutations and invoking different theorems to no avail.
All this happens while someone else who is simply smarter walks by and goes "oh, have you thought of trying this?" and suddenly everything made sense. He solved it. He stole the puzzle from you and completed it for you.
That class was how I knew I am not meant to be a theoretical mathematician. And that no matter how many movies of cool genius mathematicians I see, no matter how much red brick and history lies behind the shadows of the buildings I am sitting in, no matter how hard I try, somethings are simply beyond my capabilities.
At the end of that year, the thought of medicine started sprouting somewhere deep in my mind. It took me 3 more years to accept it and go on to go to medical school, but that class was the turning point.
