When you can't tell if someone legit ships that.

"Dude, don't say you ship that in front of me! I'm an Ererivamikarmijeanyumikurispringles shipper!"

"What?"

"Eren x Levi x Mikasa x Armin x Jean x Ymir x Historia x Sasha x Connie."

"Do you ... mean that?"

"It would make a great Nine-some."

Or:

"Don't say you ship that! I ship Jean x Ymir!"

"Wait are you serious?"

"..."

"YOU'RE SERIOUS?"