I've always wondered what makes a person develop into a "corrector," the kind of person who, when faced with a trivial typo or mispronunciation, will pointedly interrupt someone as though they had committed some profound crime against humanity and correct them with a snotty, condescending tone, regardless of context. I guess it's some inferiority complex. It allows one to feel superior, even for a brief second.
Being an atrocious speller, verging on dyslexic, I've had to live with these people all my life. They tend be people with a strong need to have others follow sets of rules or socially mandated guidelines for behavior, or, as is more often the case, people who have these controlling needs but have repressed them, so they balloon out in odd places.