[The Bone2]

exactly.

Compare the quality of one Big Mac to the next. Don't compare the quality of a Big Mac to a Steak from Peter Luger Steak House.

Compare the quality of a 2008 Toyota Camry to another 2008 Toyota Camry.

Quality is not an absolute. It can only be an absolute if you compare items whose end product is meant to be exactly the same every time, regardless of that products' appeal to any single person.

Someone used a canned vegetable analogy earlier. I used to be a competitive chili cook. Some cooks swore by "Hunts" brand tomatoes, others "Del Monte" (or whatever). Those cooks could possibly WRONGLY claim that Hunts was higher quality than "Del Monte" or vice versa. In reality the sugar content of the tomatoes was what they were judging. Some cooks preferred a sweeter tomato, and some a more acidic. Nothing whatsoever to do with quality.