Well, if we're going to tell 'war-ies'... one of the more sobering near misses I had was quite some time ago in a C130. We were on an IFR flight plan (and IMC) between Phan Rang and Vung Tau at around 8,000' and flying at 250 knots. Somewhere in the cruise, we flew clear of cloud... if find a South Vietnamese Air Force C47 about three miles in front of us - and I mean exactly in front of us! - doing about 120k.
We found out later that he had not lodged a flight plan, but his track keeping was superb.
If we hadn't broken clear of cloud when we did, I really don't know if we'd have spotted him in time and I suspect we'd have had a rather eventful radome to rudder meeting with a roundabout 130k closing speed, which wouldn't have been pretty for either party.
We manoeuvred just enough to miss him and wagged out fingers (or was it finger singular?) at two very surprised faces as we passed them.