I gave such a dog back to her breeder.
Actually, if it was just the fact that I didn't feel much of a bond to her, I probably would have kept her longer and worked on it more, just because she was a relatively easy dog in that she didn't need much to keep her happy and I did like her, even loved her enough to cry a lot and almost turned around and kept her, but there really was no real bond and that was tough. But there were other surrounding circumstances - breeder wanting me to do stuff and pay for stuff I never agreed to with a less than stellar quality dog, dog causing issues with my existing dogs because she didn't seem to understand proper body language, plus a few more things. She simply turned out not to be a good fit for myself or my other dogs, and while I would have likely given her a longer chance if not for her breeder making the rules as she went, who knows if I would have kept her a lot longer. That, combined with a lack of any semblance of a bond, helped make my decision to let her find a new home. After the 'honeymoon' period, there was really just nothing between us, as awful as that sounds. It frustrated me a lot, too, because I felt like there was something wrong with me not to be able to connect with her.
Sometimes I feel that it's kinder to rehome a dog if there is no bond there. My bond with my dogs is part of why I enjoy them so much... and if that's lacking, well, it's lacking. And it kind of sucks for the dog and the person in a lot of ways. I felt that this particular dog could find a home that was better suited to her, and that she did! The couple she ended up with absolutely adore her and think she's the best dog ever, and I am so thrilled for her and for them.