Lying constantly about what you believe is all well and good if you have Professor Quirrell-like lying skills and your conscience doesn't bother you if you lie to protect yourself from others' hostility to your views. I myself lie effortlessly, and felt not a shred of guilt when, say, I would hide my atheism to protect myself from the hostility of my very anti-anti-religious father (he's not a believer himself, he's just hostile to atheism for reasons which elude me).

Other people, however, are not so lucky. Some people are obliged to publicly profess belief of some sort or face serious reprisals, and also feel terrible when they lie. Defiance may not be feasible, so they must either use Dark Side Epistemology to convince themselves of what others demand they be convinced, or else be cursed with the retching pain of a guilty conscience.

If you've never found yourself in such a situation, lucky you. But realize that you have it easy.