respect for sovereignty
Sadly, most of the world only respects sovereignity of countries can defend them. That is what Ukraine was forced to learn. Hence they are willing to sacrifice part of their sovereignity by joining the EU because it will help them defend the rest.
needn't worry your pretty little head
I dont worry, just pointing out what is most likely going to happen. If the UK does not rejoin the EU, they'll likely lose controle over the Falklands this century. You won't have the power projection to defend it on your own 30+ years and there are plenty of countries just waiting for payback time.
It has certainly been a success so far
It made you poorer, and much less influential down the line. What a great success story. Even your crown jewel the London stock exchange is slowly bleeding away. Not just to other European cities, but other parts of the world away.
how much they hated
Again with this Brexit nonsense. Nobody hates you for leaving, at worst we pity you. But you are not going to keep the privileges of staying in the EU after leaving.
Trying to create a land-based Empire
Again, it would be helpful to read up on European history and not the warped Brexiteer bersion. The people who founded the EU did it with the fresh experience of having survived the Nazi Empire and in the hopes that doing so would allow its' member states to not be swallowed up by the Soviet Empire.