Menachem, returning to your question as to when I am usually accosted by Lubavich missionizing Mashiach and the like, I forgot very surprisingly (!) to mention the most common situation.
When I am at a Lubavich simcha – as you know I have a number of family members and acquaintances who are Lubavichers – and am sitting at a table where I am the lone non-conformist. A glass or two (or three or four…) of alcohol usually makes the imbiber feel that it is up to him to convert the infidel, and I am harrangued by him, often with the encouragement of some of the others, to show me how my chassidus is wrong, and how Lubavich has the only true path. He has the Nassi Hador, the Navi and the Mashiach, while all I have is a belief in nigleh and a stress on tznius. (Please note, that in most instances the imbiber had very little knowledge of nigleh, and his risque comments show he has no inkling at all of tznius.)
Now I am not saying it happens all the time, but I am saying that that is the most common situation when it happens. And it does indeed happen.