Gibraltar is an issue that I raised during an academic conference at my university in 2017 when we held an event about Brexit. It has long been a controversial topic, but Spain and UK did come close to achieving shared sovereignty during the Aznar and Blair administrations, but this idea did not come to fruition because the people of Gibraltar refused to back it in a referendum in 2002. The irony is palpable because they voted 99% against shared sovereignty and 96% to remain in the EU. From a trade and employment perspective, they would be much better off being part of Spain right now. This is because that many Gibraltans work across the border in Spain or run businesses which require frictionless trade with Spain to be able to function properly, so Brexit is arguably even more problematic for them than it is for Northern Ireland, which is a point that I made during the aforementioned conference.
The territory was, of course, originally Spanish, so it can be argued that it is not a land grab, but rather an attempt to restore the territory to Spain. The people may not like it, but Spanish governments of both the centre-left and centre-right will always make political capital out of Gibraltar because it is popular with voters. The centre-left tends to be more amenable to compromise, although the shared sovereignty plan was drawn up with Aznar's centre-right government. Spain's ultimate objective though is not really to take Gibraltar back. The government would like to, but this is an unrealistic aim. What Madrid is hoping to achieve is a set of concessions or conditions which will increase Spain's influence and/or running of the territory in some way in the short-term and potentially lead to further control in the long-term.
On the topic of food standards, US food standards are so very poor that the EU has strict conditions on the food that the US is allowed to export into the EU market. I have close friends who live in the US and they regularly comment on the poor quality of the food that is sold relative to the food that they have eaten when visiting EU countries. It is a serious cause for concern and I have signed many petitions on this issue alone.
The UK is in a very weak negotiating position. Time is against this country and Trump is going to really put a lot of pressure on the UK government to accept his demands. This creates a climate for hurried, and by association poor quality, decision and policy making, especially when you consider that the Conservatives have a strong majority, resulting in Parliament being unable to amend of block legislation.