People who read often get annoyed about errors in published material. Their ire made me retire my own. However, it also brought up—not annoyance, because I get paid to fix mistakes—a screaming head full of chronic errors. Here, I will list the most common 21 grammatical errors that drive readers nuts. Maybe, you’ll recognize a few and nod your head in agreement. Maybe, if you’re a writer, you even make a few yourself…