In high school, a friend and I had an inside joke known as the “killing kittens” rule. (I am not going to discuss killing kittens any more graphically than just using that phrase, don’t worry.) The rule was something we had observed in our romantic lives – that even if a white-hot crush on a cute person cooled over time, it would still remain alive, in some form, because the person was no doubt still cute and funny and smart, etc. For crushy feelings to actually, fully dissipate, something pretty extreme would have to happen. Something like, oh, I don’t know, finding out that they killed some kittens.
(To clarify, this never actually happened. It was just an example of the kind of thing that might make an infatuation shrivel up and die, and the name stuck. For years afterward, when one of us would sigh, moony-eyed, about someone we thought we’d gotten over months ago, the other would say with a resigned shrug, “Killing kittens,” and we would nod our heads with grim acceptance.)