Does everyone share the same meaning of life?

We began the discussion of existentialism with the idea that all the things that we make up in our minds to be the meaning of life, actually have no meaning at all. Or, rather, maybe they do have meaning to our shallow lives, but the meaning is all fake; something that we as humans socially constructed as a system of which to live by. What confuses me about this approach is that by saying that happiness, relationships, and love are all just part of a system, why is pain, suffering, and the anxiety and emotion that follows the idea of death not also system? Similar to what was brought up at the end of class, I think that the anxiety associated with the idea of dying is just as much a system as the happiness associated with relationships.

Everyone has their own definition of happiness and I think the same can be said for death. There are in fact several cultures that banish all anxiety-arousing ideas of death and turn them into something of which to celebrate. I think that by classifying the emotion of death so broadly, existentialists are not taking the entire human race into full account. By saying that we create these social constructs of ideal happiness (the left side of the board) to mask pain and suffering, "existentialists" are making pain and suffering into a system itself and therefore, it seems to me that there really is no way to truly escape the system, or to simply exist. 

While spending time in prison, Meursault remarks, "if I had had to live in the trunk of a dead tree, with nothing to do but to look up at the sky flowering overhead, little by little I would've gotten used to it..." (77). According to what I understand as existentialism, this seems to be what would be classified as authentic living, or living 100% detached from any of these social constructs. However, I feel that many would agree that living in a hollow tree trunk is not truly living your live to it's fullest extent and it seems to be hard to find meaning in that. While I understand that the benefit to this sort of life would be to have compete control over your life, it makes me question whether living detached from the system really worth it in the end.