Some video I seen on 4chan or 8chan or something years ago where some lady's filming with a dashcam while driving with her kids down the highway behind a truck stacked with bricks. A random brick comes flying off the truck, goes through the windshield and hits the lady in the head. The car starts to drift off to the side, there's a few moments of silence before the kids realize what happened, then they just burst into tears and start freaking out.
I've seen some pretty gory and fucked up shit, but that one really stuck with me. The randomness of the whole thing, the kids screaming and crying in the back seat when they realize their mom just died. You can't even really see anything other than the windshield but that almost made it worse.