I know I do even though I try and tell myself I don't because I think I know where I'm going after I die (according to my religion). Regardless of my faith in what I believe, there's still no one who can tell you for 100% sure what happens after you die. I just feel like I have so much to do during my life here on Earth that I don't want it to end suddenly. I'm also afraid of dying a horrible death and suffering, such as being burned alive or being trapped underwater and drowning. Just an overall scary concept, I suppose.