I am not happy in a life that has suffering and misery. I am only happy and optimistic in a life free of those loathsome things. I would also not be happy knowing that I will just forever die one day and that be the end of me. This is because I would be utterly inferior and of no value to myself anymore if this was the case. So I am hoping that I am an eternal soul.
Life would also have less meaning to me knowing that I don't get to have the eternal blissful life I value so much. So let's pretend that an eternal blissful life really did exist, then that would make this life more meaningful since that would mean I get to live forever, be forever happy, and don't have to worry about any suffering, illness, misery, disease, or death anymore.
I would finally be free. I would finally be free to live happy for all eternity and that, to me, is all that matters and is the most sacred gift to me.