Here is my 2 cents worth!!! I'm not going to try and tell you what you feel or how you should feel, or that you don't like the quilting process, etc. So, here is my idea.
I suggest that you post a message on here and see if there is someone on this QB, who lives close enough to come help you learn to love your machine. Someone to teach you and guide you. Someone to make suggestions about thread, tension issues, loading the quilt, etc. Maybe someone who has had similar problems. It could be worth the time and you might even make a new friend in the process.
Try a few different threads and see if they can get you to at least tolerating your long arm. Then maybe you can practice and see if you two (you and the longarm) can get along. THEN, if you still don't like quilting on it, you can sell the thing, and find you something that fulfills your needs. You would then know you had given it every chance and it would be time to part ways.
Sorry for all your frustration!!!! Take a deep breath and Good Luck!