One concept I consider in justification is the number of potential realities associated with a statement. For example, let's say I think my dog has just talked to me. What is the possibility that explains my experience as true? The only option is that my dog actually just talked to me. But the number of alternate theories is manifold: schizophrenia, drugs, trickery and special effects, a ventriloquist in the next room, mis-hearing, etc.
The problem with this is that almost ANY proposition has a greater number of alternate theories than what appears true. Even something simple, like “this apple is red.” The only theory that explains it as true is that the apple is actually red. But it could be white in red light, or green in purple light, or I forgot I'm wearing red-colored sunglasses. The numbers on the alternate side are smaller, because the statement is so simple, but they still outnumber the truth theory. I think Occam's Razor was invented solely to deal with this interesting dilemma.
In light of this concept, I find the manifold religious theories to be immensely problematic, especially for those who are true believers. Because many of them believe that the right religious belief, usually theirs, is critical to the correct life and a successful afterlife. But the stunning number of religions must make this scary. If you are wrong, you're fucking screwed. I wonder how people are able to rationalize this problem.