Reckless, it sounds as though you may be trying rather too hard, too hectically. I'm sure in time our other readers will have some useful advice, based on their own experiences, too. I've met some rather unpleasant cats in my life, but that doesn't mean that I didn't find a marvellous cat with whom we had a great 17-year relationship until she died of old age ---- by point being, don't give up on a whole species because you found some bad specimens. Also, consider seeing a personal counsellor to explore this in more depth --- after such a long series of failures, maybe there are some ways in which it would be useful to brush up on your techniques, to become better at selecting and maintaining relationships