What does “a black cat ran between them” mean in Russian?

In Russia a чёрная кошка crossing your path means bad luck, and some people will stop or spit over their left shoulder before walking on. The cat also lives in an idiom: между ними пробежала чёрная кошка, “a black cat ran between them,” means two people have had a falling-out and aren’t friends anymore.

Неудача is the clip’s word for “bad luck”: удача is luck, не- flips it, and приносить неудачу is “to bring bad luck.” The speaker here takes the other side: я люблю чёрных кошек, they’re красивые and милые.