Why do people fret so much about doomsday?

No one knows for sure what exactly the future holds in store for us. It is certain that things will happen. Bad things will happen Good things will happen. I do find it compelling what some indigenous cultures had to say about a future point in time when humanity would experience changes. Not necessarily the Mayans, they really never said the world would end, they just concluded their calendar. But other civilizations such as the Hopi Indians had predictions that were very compelling. They spoke of "The Great Purification" and that the earth would cleanse itself. Also Mother Shipton, Baba Vanga , Edgar Cayce, Father Malachy, Maria Espranza, and a host of others made futuer predictions for a time that is seemingly similar to now when mankind would experience drastic changes. I really cannot say for sure any of them are correct but you have to marvel at the coincidence of them all saying almost the same things. I guess we will all see soon enough.