I knew my friendship with my BPD ex-best friend needed to be over when her extremely athletic and sensitive Throughbred that I had done the majority of the training on bucked her off one day. That horse didn't have a mean bone in his body, and I knew something must have been seriously wrong with her energy for him to act like that. She blamed him, I knew better.
The dogs would also go nuts when we would fight, barking and getting in between us. Come to think of it, the majority of the cats stayed away from her too. I always trust an animal's instincts; I think maybe it's the fact that they have no ego standing in the way of their intuition. While I sit there and analyze away my gut, they just listen and react to it, for good or bad.