The part that baffled me the most was how the decision to Brexit seem be driven mostly by immigration. But the UK was one of the few EU countries that wasn't part of Schengen. They had an actual border with the EU and could control their immigration!
Not only that but the French helped the UK keep migrants out of the island (migrants were a hot topic at the time), which meant that good relations with the French, and by extension the EU actually helped.
There were no limits on legal immigration from the EU. Of course the endless stream of East Europeans had mostly dried up by the time of the referendum and most immigrants (especially the type a lot of Reform/Brexit supporters don’t like) were coming from third countries which had nothing to do with the EU..
Not only that but the French helped the UK keep migrants out of the island (migrants were a hot topic at the time), which meant that good relations with the French, and by extension the EU actually helped.