For 5 years people asking "but what about the Northern Irish border?" were told it would be fine, we'd have magic technology sorting customs, we'd have no border in the Irish sea, it'll be grand so.
Then Johnson stormed in and promised a border in the Irish sea which got a few backs up but somehow was billed as solving the problem by the UK press. Now however we appear to have a border in Northern Ireland and one looming in the Irish sea so people are still confused and some of them are angry and a fair few are armed so...