Greetings!
This thread has a lot of nonsense and most of the so-called reasons given to explain the "short conversations" are garbage.
The reason doesn't have anything to do with JW mentality or short-attention spans or the theology of the religion or anything like that. It is just a function of time and location. The very same people who can't seem to speak more than a few sentences at the KH will talk endlessly for hours at congregational picnics, at the lunch-hour at the Assembly, at home, or even walking in the ministry.
The fact is that most people arrive about 20 minutes or less before the start of the meeting, with most coming in maybe 10 minutes or so before the start. And afterwards, most have other things to do after giving up 2 hours of their day and leave fairly quickly. There simply isn't time to spend in any lengthy conversations. This factor alone makes any such deep or personal topics or discussion which require explanation and background virtually impossible.
Add to this the fact that Jehovah's Witnesses respect the place of their worship, consider it God's House, and thus many topics like the latest episode of Desperate Housewives or problems at work or home, etc. are not considered proper by most. Also there is specific direction from the Society not to do any business dealings at the Kingdom Hall, which in the normal world makes up a large part of one's normal conversations with others.
Finally, a lot of this observation depends upon the particulars of the congregation and the larger cultures involved. I have been in predominantly white, black and hispanic congregations and in the latter two these definitely tended to be longer and more in depth conversationalists than in the mostly white congregations. But again, even in these "warmer" congregations the same above factors were present which result in typically abbreviated dialogues and rather superficial chit-chat.
Common Sense,
Eduardo Leaton Jr., Esq.