I admit that I am a stickler for grammar. It's also apparent to me that not everyone feels the same way. If you are a writer, however, you should be on top of the game with grammar and punctuation.
The chart above shows the most common grammatical errors. I remember doing pages and pages of grammar exercises in English class in grade school, junior high and even some in senior high. By senior high, we were expected to know the differences in the spelling and meaning of the words shown here. Occasionally, we'd have a short review or a shouting lesson when too many of the incorrect spellings were used in an essay paper. I remember my Freshman English teacher lecturing on same with fire in her eyes and smoke ready to pour from nose and ears. My, oh, my--she was irate about what she termed 'careless' errors.
Perhaps her word--careless--is right. We can be so intent on the gist of what we are writing that the grammar/punctuation part slides by us. That's the reason we write a first draft, then go back and edit more than once. It's a good reason to put your work up for a critique by one other person or an actual critique group. Others will find these small errors quicker than he/she who wrote the words.
I have seen news flashed across the tv screen that uses words like your and you're incorrectly. When that happens, I actually cringe. The one thing I need to remind myself of is that half the people who see that error will not even be aware of it because they do the same thing themselves. Am I try to put people down by saying that? Not at all. It's merely reality.
As writers, we need to learn to care about the grammar and punctuation quotient in our stories, articles and poetry. We should set the example for our readers and, yes, other writers. As important as what we are saying is, it's also of relevance that we say it in the proper way.