Accidental Invitation
When you're inviting individual friends to something, but other friends over hear you and ask to join, when you don't want them to.
Person 1: "Hey, Person 2, wanna go sledding tomorrow?"
Person 2: "Yeah, sure."
Person 3: "Oh, cool, sledding! Can I come?"
Person 1: ".......Okay." (FUCK! I HATE PERSON 3, HE RUINS EVERYTHING! Accidental Invitation sucks!)