I think being able to make such people understand is an important social skill. They obviously understand the meeting thing. Why is that? You need to react to e

I think being able to make such people understand is an important social skill. They obviously understand the meeting thing. Why is that? You need to react to every interruption in the same way you would if they interrupted a meeting. Allow yourself to be genuinely outraged that they would even think about crossing the threshold. It's OK to have boundaries.