Most Christians should meet somebody who will tell them: "You are going to hell."
I say most because I don't know if we're all strong enough to handle it, but I think it would be healthy if we got a taste of how it is to be on the other side of our own beliefs about the afterlife.
I have many friends who are atheists or agnostics of some kind from college, and all through college I held to pretty conservative views of salvation. Still do. Now they've been tempered for a long time by a more inclusivist strand of thought, and an emphasis on not judging anyone's individual salvation. Still, I can't imagine I never inadvertently insulted anyone simply by believing what I did, which boiled down to, qualifiers or no, all other things equal: You're going to hell.
Don't get me wrong, I'm well aware that there are people who think I will spend my eternity in torment because I am a Christian. Oddly enough, though, the more memorable times I've actually gotten a full, realization kind of taste of it, have been on the Protestant-Catholic divide. The first time was back in high school when one of my Catholic friends made some comment (which did then, and still does, strike me as kind of theologically simplistic) that it would be necessary for salvation to believe that the Eucharist was really the Body and Blood of Christ.
And now that I am a Catholic, and I do believe all this nonsense about the Eucharist and Communions of Saints, etc., it's not even so much a moment, but merely having a friend who desperately tried to talk me out of it (actually, someone close to him did, but I don't think he disagreed), and whose church would seem to be teaching him--if it mentions the Papists at all--that my salvation is dubious. Now granted, that's just part of the divide that is a consequence of choosing communion with Rome. I should say that I am grateful and touched that he, and his friend, were loving enough and caring enough about my spiritual health, to say what was said. But it introduced a palpable divide that I can feel every time I see him, an awkwardness introduced into all those situations, that wasn't there before. And the phrase "you're going to hell" was never even used, or even necessarily implied. Just there, under the surface, a highly uncomfortable possibility for me in the theology of the other.
Now I always felt a little bit awkward if I knew I'd said anything directly to any of my non-religious friends about the afterlife. But I do wonder whether the way I feel around my friend now is the way they sometimes felt around me. It's a feeling of being on the other side, of knowing someone is seriously concerned about the state of your soul (in a way they wouldn't normally be, that is a healthy concern after all.)
And I wonder if maybe it's not a good healthy experience that most Christians should have, to go out and meet someone who makes them realize--not just know in some academic sense, that someone believes they are going to hell.