Oh boy, this one's a doozy. Nearly seven minutes long, "Dear John" is full of some of the most emotional lyrics Swift has ever written. The way she spits out lines like "You are an expert at sorry/And keeping lines blurry/Never impressed by me acing your tests" with such fervour makes you feel like you should apologise to her for something even if you've never met her. It's a sad story with an explosive ending guaranteed to give you chills every time you hear it.