Is that true? I find it almost impossible to really even think about. It makes me feel like I'm falling down a well, and the fully-realized concept of non-existence is the sides, and my mind is scrambling against it but just can't quite grab ahold, but gradually becomes more disturbed and my stomach sinks further from the falling the longer I try. It's full-on Lovecraftian/Cosmic horror.
And I think I'm relatively well-adjusted and accepting-of/content-with reality on that front, for a non-religious.
[EDIT] minor grammar fix
I want nothing more than to never cease being, to never stop learning and experiencing and seeing how the world and I change, and the knowledge that one day I'll stop fills me with intense dread and sadness. It's utterly egotistical, but I don't want there to ever be a time where I don't exist. Which is ridiculous, because I didn't exist for the huge of time, but now that I'm here, I really don't want to stop being. The idea that instead of moving on or experiencing something new I'll experience nothing, and I'll never come back from it, never get a chance to experience anything ever again, is horrifying.
I had a very close friend who was deeply interested in spirituality and philosophy and who devoted a good part of his life to understanding our existence. Nothing prepared him for the painful cancer death experiences he endured. Intellectual perceptions are nothing against our first and only viceral experiences of death....
I don't think that's true. Our experiences with death, whether it comes from others dying or us having a close call, forces us to contemplate our own end. Memento mori and all that.
Most people are ok with not existing. It's the dying part that is tough to deal with.