Adjusting for correct expectations, I haven't had a single camera disappoint me.
But any camera I have bought or otherwise received has been to a professional CLA, either before or after I got it, and they have all worked faultlessly, and I'd like to think because I took that precaution.
The only camera that truly faulted me was the Holga, but you have to have no expectation at all using one. On a hot day the 'tension foam' came unglued and rolled itself up into the roll of film that was in the camera. Then it scratched my film to become unusable, in spite of trying at least five different known tricks to avoid that from happening. I took the lens and shutter mechanism off the camera, placed the rest of it on the side walk and ran over it with my car... Man that felt good!