Grossly generalizing the human race, there are three categories of believers:
1. Those that are born into a religion
2. Those that embrace a religion upon marriage
3. Those that embrace a religion after years of soul searching
Most people who fall into the first category take their religious beliefs for granted. Being a believer by birth often makes someone feel too secure that he reasons that there is absolutely no need to dig deeper into his religion. This false sense of security begets complacency and apathy towards more important aspects of the belief system, and these in turn, lead to a superficial understanding of the religion. Most people, including yours truly, fall into this category.
The second category consists of those who only pronounce (albeit hesitantly) their "new found" beliefs upon marrying their spouses who are believers of other religions. More often than not, these people lack true appreciation of their new beliefs, simply because the ultimate reason for their conversion is to win the hearts and minds of their spouses and in-laws. There is no clear distinction between the first two categories, with the exception of the second group of believers having an extra religion or two to add to their portfolio.
The third category of believers is essentially what we mere mortals should strive for. Starting with a clean slate while being on the outside looking in, free of prejudice and bias, this breed of believers are blessed in the sense that they are not influenced by any prior religious and philosophical doctrine in their quest for the truth. Thus, they are free to roam and explore a multitude of uncharted terrains laid before them, until they ultimately reach their destination where the truth is finally laid bare. The vicious cycles of confusion, sorrow, ambivalence, anxiety and helplessness that accompany them throughout their journey only serve to solidify their enlightenment, whilst building a mighty foundation for true appreciation and understanding.
In an ideal world, one would dream of achieving what the last group of believers have attained. But is pure enlightenment solely attainable through a fully "empty glass"? If a man of faith were to wish to embark upon such journey, would it then amount to an implicit renouncement of his belief? Is it even remotely possible to truly explore and appreciate another belief system with indoctrination clouding one's judgement?
One can only wonder.