The difference you don't get is about law. The EU might be regarded as a free trade area with a bunch of extra features related to common rules, laws and court

The difference you don't get is about law. The EU might be regarded as a free trade area with a bunch of extra features related to common rules, laws and courts. Everyone is subject to the same law and same courts, and that enables a lot of optimisations, some big, some small. You can see this for the current bivalve affair. The EU rules basically say that since everyone from the grower to the final consumer answer to the same court and obey the same law, various processing can happen anywhere along the chain and the same liability/hygiene/safety rules apply everywhere. However, if the grower is in one legal domain and the consumer in another, then some processing has to happen within the grower's legal domain, before it crosses the border. The UK would like to have the benefits of the optimisations, but decide on their own laws and not answer to the same court as the others. That won't work, because the benefits derive from being within the same legal domain. No amount of good or ill will will change that.