"Are we there yet? Don't tell them I'm here. They had a fight. I know you want to stop it. Protect her from him. But you're young, you don't see what I see. It's not just that she makes him a better person, she does, but he changes her too. Damon challenges her, surprises her, he makes her question her life, her beliefs. Stefan is different, his love is pure. He'll always be good for her. Damon is either the best thing for her or the worst."
P.s Sorry if some of this quote is wrong I couldn't find the whole thing but if I do I'll re-write it.