No matter what message you are about to deliver somewhere, whether it is holding out a hand of friendship, or making clear that you disapprove of something, is the fact that the person sitting across the table is a human being, so the goal is to always establish common ground.
Everyone thinks that just because you have a Scouse accent, then you must be 'on the rob'.
If North Korea is allowed to maintain its nuclear weapons programs, other nations may well follow suit and some may buy such weapons from the North Koreans.