One thing that has always been hard for me to handle is knowing that I will never be able to do or learn all the things I want to do in life. I will never be fluent in every language; it's unlikely I'll ever be fluent in more than English. My house will never be 100% clean and organized; I can't even stay on top of the dishes most days. I will never understand entirely the politics and economies and cultures of the various nations of the world regardless of the effort I put into learning as much as I can about that sort of thing. I will never read every book that would be interesting and/or useful to have read. And thinking about what I don't know about the sciences is too frustrating to bother with. I just want to meet every person who has ever lived on earth, have a good long discussion with them about their life and all the wisdom and knowledge they have acquired over it's course and experience everything they've experienced (skipping over parts that involve physical pain, of course; there are some things I don't care if I ever experience, and what it feels like to have your fingernails pulled off in a Vietnamese prison camp is one of them, thank you). After that, can someone please explain to me how everything that humans don't understand yet works? (Side note: Notice how people always throw a "yet" into a statement about the limits of human knowledge? I love that.)
I have to believe in life and learning after death. I'd go completely mad without it.