To me, the most frustrating people to try to reason with are siblings and relatives.
I have four siblings that are all Christians to some degree or another. I have learned over the years that arguing with them on that topic is useless. When I get them in a logic trap they make a joke about it and change the subject. But lately with the economy in such critical state I have tried talking about the economy and such, which, of course leads to metaphysics, logic traps, jokes and change of subject. I'm thinking toleration can only go so far.