Where I'm from, it wasn't quite like that. Sure, there were those who couldn't think or do anything but Watchtower business, but even the local elders and pioneers would think those people were creepy and mentally ill. I knew one guy who spent 4 hours every single day on his "personal study." Nobody liked being around him, not even his wife.
If anything, I think we were all too happy to talk about something other than the same damn thing we were instructed to listen to, read, meditate, and speak about every single day of our lives.
Our conversations in service we're usually about entertainment, hobbies, news, humor etc. Rarely intellectual (I tried sometimes with little luck...), but also rarely boring.
It's part of what kept me going in the religion for so long. It's also part of why I sometimes defend JWs from the most absurd of accusations against them. I couldn't see how bizare it really was because I really did have some cool friends who somehow remained normal-ish despite how much of their lives they gave up to WT.
There were always some people who treated it like a religion and some who treated it like a cult. One problem was, those who treated it like a religion wouldn't ever want to moderate those who treated it like a cult. Who were we to interfere with someone else's "zeal"?