for me, every religion is a socialized, ritualized, and spiritualized effort to attain happiness.
although undeclared and often unrecognized, a religious construct, be it christianity, buddhism, islam or even a cult, actually functions to offer the practitioner a defining lifestyle, which should enable him/her to gain or maintain a happy state of mind even under the most unfavourable circumstances.
as the practitioner believes that the all-powerful or omniscient holy being has the best intention for him, is trying to save/test him, and will eventually take care of everything for him, all he can or need to do is to reply on his 'god'. by so doing, the religious practitioner hopes to enjoy maximum happiness for the longest possible period of time while still alive.
in practice, religion has turned out to be perhaps the most effective, most popular, and most readily accessible approach for humans in their efforts, consciously made or otherwise, to happifying their daily existence.
no matter whether religion is or is not a spiritual opium to humans, it serves a fundamentally good purpose. that's why most religious practitioners live a happier life than non-practitioners.
as time goes by, most religions have, alas, been reformed and transformed to the extent that they fail to fulfil their true and even basic functionalities. this seems to be especially obvious if we pay attention to the many meaningless or unnecessary formalities as well as all kinds of scandals with regard to religious practices in today's world.
(i have tried very hard, and still wish to be a practitioner of a 'religion', but just could not)
all humans have a natural tendency towards a positive psychological condition. in other words, all people were born to be happy. this becomes self-evident upon two facts: 1) children tend to be happier than adults; and 2) people become unhappy as a result of internal and/or external stimuli/influences.
indeed, all people are naturally happy (or happy by nature). this natural state of mind is constantly disturbed simply because we become unable to cope with those influences making us unhappy as we grow and live on.
either a new religion needs to be formed sooner or later to help people gain or maintain happiness, or contemporary practitioners should return to their true and 'original' religions.