Eight or nine years ago I submitted an essay to Sunstone that began "One day my companion Sister Knight and I met a 'weird funky lady,' as I described her in my journal, who tried to explain to me her adoration of some reincarnated Buddhist monk." It did not begin "One day when I was a Mormon missionary, my assigned working partner or companion (to use the term we employed for said assigned working partners) Sister Knight and I met a 'weird funky lady,' as I described her in my journal (which I kept because doing so was a religious commandment I was obligated to obey because angels might some day quote from my journal if I said something inspiring), who tried to explain to me her adoration of some reincarnated Buddhist monk, a conversations many Mormon missionaries wouldn't have had because they generally talked to rather than listened to other people about religion."
It's a good thing the essay didn't begin with the second sentence I offer above, because that sentence sucks. But if I had submitted that particularly essay to a mainstream secular journal whose readers weren't necessarily familiar with Mormonism, I would have felt obligated to provide lots of background and context--maybe not in the first sentence, but certainly SOMEWHERE in the essay. Whereas I knew that as soon as a Mormon audience was informed that I had a companion named Sister Knight, readers would assume, correctly, that I was a woman somewhere in my 20s who had elected to serve a mission.
Despite or perhaps because of their self-proclaimed and cherished status as a peculiar people, Mormons hate to be misunderstood. As a result, when they talk about their religion, they explain A LOT. Sometimes--perhaps usually--they explain TO EXCESS.
Two groups especially prone to excessive explanations are missionaries and Mormon writers.