Have you heard of the word "Stickler"? I first encountered it in Lynne Truss' book entitled "Eats, Shoots and Leaves". A book about the correct usage of punctuation marks.
A "Stickler" is someone who insists on something unyieldingly. And according to the book, there are a few people on the planet that are sticklers when it comes to grammatical errors. Those people who experience an itch to correct every error they see. They feel uneasy when they see these errors and they couldn't rest until they are corrected. Why am I discussing this? Well, I'm afraid I am one of these sticklers.