I had a co-worker spout a conspiracy theory that would've required THOUSANDS of people to be in on it and he saw it as quite legit.

I asked him if his family had any secrets and he replied "Yes, of course" and I then I said "Do you know any you're not supposed to?" and he said "A few, yes". I hit him with "If the people in your family that want a secret can't keep it as such, how do you think thousands of strangers would do so?"

He hoped on the "Well they'd all be killed or dead if they said anything...". I tapped out.