Uh, I have some questions about religion, can you answer them for me?

How do religious people feel about their particular religion when compared to the other religions and denominations? Does the size matter?

For example, do some religious people think the monotheistic religions are more valid? What makes one religion seem in high regard, and another not taken as seriously?

When a new branch of religion is created, do people check it out and see if they want to join it or something? I always wondered how the process happened. For instance, some people say “I used to be a methodist, but now I’m…...”.