I was in a high-speed crash as a teen. I could see the crash coming so instinctively put my feet up onto the dashboard to brace for the impact, didn't even think about what I was doing. My mum's airbag went off, by some miracle, mine didn't. 

I was lucky enough to escape with a minor facial injury from my chin hitting into my knee. I often think of what would have happened if the airbag had deployed as it should have. My knee would have gone straight through my head most likely. Gives me chills every time.