My husband and I adopted a dog 9 weeks ago. He was really good...picked up on house rules really quickly, playful without being pesky, always up for a walk but not an overly "busy" dog - actually pretty chill for a young dog. The only thing is that he hates our cat. His foster told us that he was curious but easily distracted when it came to her cat. However, we never found that to be the case. He stalks him relentlessly. He persistently seeks him out. If he can't get near him he'll have an absolute meltdown. We had been working with trainer who insisted it was an insecurity issue and once he decompressed he'd be fine, but it just got worse. Our vet told us that it was a drive that we wouldn't be able to train out of him and that we would only be able to manage the environment. She also pointed out that at some point it would just come down to who's faster. I finally contacted the person who does behavioral assessments for a local GS rescue and she agreed with the vet. In the meantime, the cat just shutdown and developed bladder crystals due to the stress (ironically the only other time this has happened is when we lost our last dog - the cat's bff) which is potentially fatal for a male cat. So we made the difficult decision to give him back to the rescue. He went home with his new family this past weekend and I have been a mess since. I miss him so much. I feel so incredibly awful. But I also felt awful while my cat was miserable. This has been the first time an animal has come to me and not lived out their life with me...I wouldn't wish this decision on anyone