Ok for example, I start by saying,"Unfortunately there was a giant evil pillow on the the loose; then the next person would say...Fortunately I had a knife with me and stabbed a hole in it"
Ok lets start. Unfortunately I was being chased by an elephant...
Unfortunately, since they studied how to turn remaining humans into cats and themselves into dogs, they turned themselves into dogs and started chasing the humans/cats!
Unfortunately, after 20 million years, the sun exploded and Earth was completely destroyed. (Idk how much longer the sun is actually supposed to last, but we're saying 20 million years)