Whats one thing you wish you could see or happen in your lifetime.
Mine would be for a city-sized piece of Asteroid or Comet to come smashing into Earth (preferably the Atlantic) and not only evaporate everything around it for thousands of miles, but to create a tidal wave that would destroy New York, Washington, Miami, Iceland, Ireland, Canary islands etc.
Just the sight of seeing the huge fireball slowly rising above the horizon, to see the clouds blow-back from the shockwave, to see a mushroom cloud envelop 3/4 of Earth.
Not only would it be a sight to see, it would be "good" for humans to realise that life is more than about money and work, and everyday is a survival and we'll be back in the dark ages again 200 years set-back.
It'll probobally wont happen in my lifetime, but its happened before in Earths history and WILL happen again, one day there'll be a NEO that'll catch us by surprise, then BANG!!!!
Its not the fall that kills u, its the sudden stop at the end..