[throwaway122379]

1st of November, Boris (or whoever is PM then) asks EU for trade deal. They respond with, "great, so about:

1. Irish border and Good Friday agreement

2. EU Citizens rights in UK

3. Payment of billions to which previous UK governments signed up to as EU member

4. How will you ensure low quality food from US does not enter EU"

[bigbaguette]

This is how international trade works. It's intimately intertwined with diplomacy and each party will play according to its own interests, related or not.

Just like Russia could say "no gas for you" if you make too much of a fuss about what happened in Crimea.

Now if the UK's view of its own future diverges from the EU, it's totally normal to see complications appear during negotiations.