There is a Hungarian expression, küszöbgörcs, which literally means "threshold-cramp", and is used to describe that long conversation you have in the entryway, with all the guests awkwardly holding their coats and purses, and every so often somebody says something like "Ok, we really have to leave now, but just one more thing...", and then the conversation is good for another half an hour at least.
I've searched in vain for an equivalent idiom in English, yet I feel sure it must exist: I know English speakers are equally susceptible to this malady, it's not a uniquely Hungarian thing. I will sometimes use literal translations, like the aforementioned threshold-cramp (or doorway-spasm), but then I need to explain it, and that's less than satisfactory. (Plus it leads to more threshold cramping.)
