The Associated Press Stylebook suggests treating none as a singular pronoun when referring to the absence of individual people or things: “None of us is perfect.” That’s a style choice consistent with what many consider good writing, but there is little to suggest that “none of us are perfect” is any less valid a construction.
In editing circles, we often talk about frequently confused words, like compose and comprise and affect and effect. We work hard to ensure that our authors are using the correct words. These confusables don’t get much play in popular media—unless there are unintentional, humorous results. The more obvious or funny the mistake, the better.
The lack of a gender-specific, second-person plural pronoun is a source of consternation among grammar and usage sticklers. In our post-feminist society, the use of guys to address all-female or mixed-gender gatherings rubs some people the wrong way, for different reasons.
Fifty Shades of Grey is notorious for several reasons, including evidently tortured prose. I haven’t read it (really, I haven’t), so I can only judge by what others tell me. But one area in which this book evidently did not fail was its proofreading.