One of the many things that can get me riled is the use of "it's" when the writer means "its". C'mon, it's not difficult: "his" and "hers" don't have apostrophes, so why would "its"? And formal writing (where the mistake also often pops up) tends not to use contractions; it should either be "it is" or "its", never "it's".
Given my pedantrypassion on the subject, I immediately noticed the sentence
Perhaps it’s its forbidden nature that consumed me.
in a "Big Idea" blog post. What a gorgeous juxtaposition. Why have I never noticed such a construct before?