I got a new Pfaff a while ago (because I always got Pfaffs and this one had some "cool" features) and when I got her home she turned out to be a picky, persnickety, nasty piece of work. It was beyond "quirky" and I was extremely frustrated. Boy did I regret that purchase - although the price was OK, it was still high. My husband finally begged me to get a different machine because he was afraid that I would toss it out the window. (Yes, I was getting THAT upset).
Less than a year after my original purchase I went online and did a lot of research. My list of "must haves" and "would be nice to have" was well developed. Fortunately, we have quite a few dealers in the area so I went to test drive all sorts of machines. In the end, I decided on a Baby Lock who incidentally did not have my top "must have" feature (built-in walking foot). BUT she had so many other wonderful features I LOVE HER. In my classes everyone else had trouble with tension and thread types. I just sewed and quilted like a happy camper.
I think you are doing yourself and your craft a disservice by wrangling with your current beast. There are some very nice and reliable machines on the market that don't necessarily break the bank. You owe it to yourself to go find what works for you. Dealers who tell you that "it" is your fault, and dealers who don't give you ample access to test drive are not where I would shop. Good luck finding your happy match. Make an adventure out of it - not a chore.