i guess a smooth break up would be like, both of you agree that you want to break up and still be friends or like the other person says i still love you but things aren't working out, i'm sorry but can we be friends? and you know something like thatthen a nasty break up, which i just went throughits when, one person decides to just break up, for the stupidest reasons, and they tell you they love you but they dont want to be with you anymore and there are just so many ways to tell if a break up is bad or goodi guess the reason they start hating each other is they broke each others hearts