I just rehomed my Savannah that was a "designer cat"
She was actually a rescue that came into the animal hospital while I was working one day. Her whole litter was living in the woods behind someones house. She had a huge abscess on her side (probably where a grub had been) and ear mites and yeast so bad I am sure it damaged her hearing. I got her in good health but my other cat, Celia, HATED her. I mean hated. The poor thing just stayed hidden everyday, all day long. She was terrified to come out.
She was so beautiful too.