I was walking my dog in the woods, looking around, not giving a forget where I was going. (We do have a path in the woods.)
I hear a hiss - I look down and a timber rattlesnake is positioned at the edge of the path, backed against a tree, ready to bite my leg.
Another time, I was sitting in my mother's room using her laptop. This is before my computer was fully set up in my family's new house.
My brother was climbing up a bookshelf, which wasn't bolted to the wall yet. He was right next to me, beginning to climb back down. To my utter horror, it began to fall, fully loaded with books.
I leapt from the chair and shoved the bookshelf back against the wall as my brother stood, frozen in fear. He started to walk away after I had finished securing the shelf to the wall, but not before a large book fell and struck his back, knocking the wind out of him.
Urgh, why do I have to remember such terrifying moments so well.