Ive had three somewhat near misses, all from see-and-avoid, and two of them in controlled airspace.
First time was in Class B airspace- a Baron or similar sized light twin, opposite direction, about a hundred feet below me, and just far enough to my left that I could see it out my window.
I queried the controller, and they apologised for not alerting the two of us beforehand. The other pilot then made a joke about big skies.
Second time was out in the great wide expanse of class G, when a Conquest made a single broadcast alerting me that he was descending from above me, on my reciprocal track, while I was climbing. All attempts to contact the other pilot by both myself and another aircraft who chimed in to help out were fruitless,
and getting that little feeling in the pit of my stomach, I altered heading to the left.
My passengers pointed out the conquest to each other as it barrelled past, right through where I would have been had I not taken a detour.
Third time was just before turning base in a GAAP zone. The other aircraft, a single engined Piper variety, appeared out of nowhere, 45 degrees off my nose, heading straight for me, same altitude.
The other pilot saw me at about the same time I saw him, and our rapid left turns enabled us to pass with at least 10, if not 20 metres separation.