heard (good or bad)? The thing that just rocks your world.
I've mentioned it here before, but mine is when I learned that 3 of my cousins are actually my half-siblings. My uncle couldn't produce viable sperm and he and his wife asked my dad for samples. After consulting my mother and getting her approval, he donated.
To this day, those three cousins don't know the truth. Nor will I tell them (unless something happens where I or my child need a kidney and I need a donor, haha).