As children, Prussia would always call you a useless, pathetic, crybaby. He always said you were only around because of him.
Prussia: "You are a useless, useless, useless child. You're the world's most useless child."
Russia: "..."
Prussia was always there. To help you back up, to make sure you knew to only come to him.
When you two became adults, it swapped. You would constantly call Prussia useless, pathetic, and lonely. You always said he was around because of you protecting Prussia.
Russia: "You are a useless, useless, useless child. You're the world's most useless child."
Prussia: "..."
Prussia was so lonely, one day he left your side. You saw him covered in wounds.... Then he was gone. That child was no more.
Russia: I am a useless, useless, useless person... I am a lonely, lonely, lonely person... He got so lonely and now that child is no more..."