My husband had a terrible mismatch with a dog.
He desperately wanted a Nova Scotia duck tolling retriever. We searched for a litter, interviewed breeders, and found a litter sired by the same dog who sired his favorite Toller.
95% of the time, Rio was a wonderful dog- intense, smart, incredibly trainable, responsive. But, as he matured, he developed a severe case of possession and place aggression, which was amplified by my husband not giving him enough exercise, consistency, or discipline. He repeatedly attacked our other dogs, sometimes sending them to the vet. On more than one occasion, he bit my husband when he tried to take something from Rio; once requiring a hospital visit. He would snap if he was suddenly woken from sleep, once biting my husband’s face.
My husband took him to a behaviorist, but he simply couldn’t- or wouldn’t- follow through with his recommendations and training schedule.
In the right hands, with someone who would give him the structure and consistency he needed, Rio was a great dog- he never bit me, and as an only dog he would make an incredible working animal.
So, we sent him back to his breeder (with full knowledge of what Rio was capable of), who eventually rehomed him. As far as we know, it went well. It was horribly, horribly diffcult, but in the end it was probably the best thing for all involved.