As far as I am aware most if not all religions promise the possibility of eternal happiness in the next life. However the concept of eternal happiness is impossible to understand. How could we be happy without our negative emotions - don't we enjoy our negative emotions sometimes (watching a sad or scary film)? Aren't our negative emotions a release? People who are happy for extended periods, e.g. people in-love or people suffering from mania cannot keep up being happy because it is exhausting and also people in these states become irrational. So why do we buy into the concept of eternal happiness in the next life so easily?