I envy people who have faith. They have most of life's questions answered for them by their particular set of beliefs and have a support system to fall back on in times of crises or doubt.
Because faith is not related to reason, it is something which you either have or you don't. You can not prove to someone that what they believe in is wrong and expect them to change their belief system. They will just dig in their heels and try to find arguments, no matter how convoluted, in support of their faith.
Cultural beliefs grow out of indoctrination, whether intentional or unintentional. Parents passing on their belief systems to their children, or the kids learning from their peers or from someone else they admire and wish to emulate. I am not criticizing the parents here, because I believe that it is their inalienable right to do so. Kids growing up in a culture will naturally be affected by it and have questions and it is the parents' right and duty to explain to the kids the reasons or thinking behind the particular rituals or acts. They have to do that to ensure that their children grow up as well-adjusted adults in their culture.
But if that is so, how come people convert from one religion to another? Exchanging one belief system for another is not easy. Perhaps those who convert do not have a strong belief system to start with. In the developing world, people dissatisfied with their social status in their own culture, convert to another religion where they believe they will be treated more equally. Because most of the time, religion equates culture. When you leave one religion and convert to another, you are actually leaving one culture and embracing another.
There are some free-thinking individuals who actually question their religion and eventually become dissatisfied with the answers and leave it to become hardliner critics. Most of them end up as atheists. Some are branded as apostates.
And what about shopping for religion? 40 million Americans each year move from one religion to another, according to that report, which is an astounding number, if it is true. But it should be good fishing for all those various sects and religions trying to increase their numbers. And then, if someone is shopping for a religion, it means that they do have some sort of faith to begin with. All that they need is a convenient coat-hook to hang it on.