When your friend has the same favorite character as you do and suddenly you become extremely protective of that character. Like, they'll say the smallest thing about them or about one of their character flaws and suddenly you feel rage like no other and it becomes your life goal to defend that character.

Or worse.

They start reading a series and say they don't like your favorite character...

This happened to me with Annabeth. My friend had started reading PJO and I was like "OMGs DO YOU LIKE ANNABETH?!?!"

And she was like: "She's kind of annoying..."

And I just sat there for a minute in complete awe that someone could dislike Annabeth.

But it's fine. She finished the PJO series as well as HoO and now we fangirl over Annabeth all of the time because she finally saw the light and happiness of loving Annabeth.