O Pioneers!!! - Bad Scene, Aaron's Fault lyrics

I don't understand how someone can say that they love something, and just walk away Just when it gets hard, and you if you love something, you have to fight with every breath that you take Till your muscles stop moving And no longer reaches your lung, and the air that you breathe no longer reaches your lungs And you think your actions through We think them through And it makes me sick Of all these kids that say, my scene s**s, and then they just walk away And it's hard to sit through every fight with you When you just get up and walk away every single night And when you get up to f**ing leave, you just walk away When if you love something, don't walk away