There were red flags raised on a regular basis, when we were bible students.
One that stands out, was when I mentioned that I liked shopping at garage sales. The husband said, "You gotta be careful. You don't know if the people might own a Ouija board or some other spiritistic items, and their stuff could be possessed..." The wife quickly nudged him and that weird comment came to a halt. I blew it off and didn't really pay attention to it. It was so far off the wall. I guess the wife knew we weren't ready for that truth yet...
Now, I hate to say... EVERY time I talk to a JW, they say something that makes me raise my eyebrows (and try not to bug out my eyes or make audible noises out of shock).