Although there are numerous religions in the world, it is interesting to note that the belief in the afterlife amoung human beings predates organised religion.
The numerous religions in the world may appear to differ in many ways, but actually they all present a fairly similar set of concepts when it comes to the question "Is there life after death?".
Most organised religions offer the promise of an eternal life in heaven if one meets certain conditions. The concept is that right now the whole human race is of a fallen nature, we are all doomed to some terrible fate upon death unless we embrace a certain set of actions and beliefs.
This fate could be an endless number of reincarnations into so called lower life forms, an eternity in a firey hell, or being annihilated out of existance. In most of these religions, it is God who judges us and decides our fate, though in some it is simply the accumulation of our actions in our lifetime that decide our afterlife fate.
Note however, that in all of these religions, ones short lifetime right now is the deciding factor of our ETERNAL fate.
Thus in our very short time here on Earth we should all be in a blind panic and rush to discover exactly what it is we need to do to avoid such terrible eternal punishment before we die. We must quickly learn what it is we must do to avoid offending God and get into Gods good books, to become enlightened, to be spiritually "born again" and secure ourselves an eternal place in heaven and escape Gods wrath.
So what's the big problem with these concepts? The big problem is that God will, according to these religions, enflict eternal punishment upon the vast majority of his creation, upon beings which not only are of significantly lower intelligence, but also have an unreasonably short amount of time and very few "clues" with which to learn what it is they must do to avoid this wrath. Does this not seem just a little unfair?
What about all those perfectly kind and loving human beings who mistakenly believed the "wrong" things?
Proponents of all organised religions often like to use the "free will" argument at this stage and say that humanity is doomed due to human error/sin/mistakes and that we must use our "free will" to take certain actions and adopt certain beliefs that will now save us from Gods wrath. But what must be remembered is that the average person leads a busy life- with school, work, relationships and so on, and does not always have the time to reflect upon deeper issues and when they do, we live in a world full of people all claiming to have the answers! Do people really deserve to be punished for all eternity for not being able to figure out what is the "true religion" in their short time here on Earth? Do you think that is really what the actions of an all knowing and all loving God would be?