Putting The Relation Into Relationship, Part 2

(Two girls, looking to be in their late teens/early twenties–one blonde, one brunette–walk in. Their arms are linked. They talk under their breath for a minute, and then laugh. The brunette kisses the blonde’s cheek and they separate. My coworker prides herself on being open-minded.)

Coworker: “Aww! Look at them. They’re so cute.”

(My coworker goes over to the brunette.)

Coworker: “Excuse me, I just wanted to tell you how cute the two of you are together. How long have you been together?”

Brunette: *thinks for a minute* “Uh, gosh. I guess it’s been, what, eighteen years now?”

(My coworker just stares.)

Brunette: *trying not to laugh* “We’re sisters.”

(My coworker doesn’t approach people she thinks are couples anymore.)