I used Grammarly to grammar check this post because, after all, your spouse gets tired of reading that same sentence over and over again! Full disclosure, this post is sponsored by Grammarly, which is an online proofreading service that promises "reviews and improves your text, correcting grammar, spelling, word choice, and style mistakes with unmatched accuracy." It'll even check for plagiarism! As you can see, I didn't plagiarize there because I a) named my source, and b) put quotation marks around words that weren't original to me.
Which leads me to some general thoughts about grammar and the rules of writing. These are just some observations from my own teaching and grading experience. If you want to learn grammar or know it better, I suggest you check out C. Edward Good's Whose Grammar Book is This Anyway? Knowing how grammar works, how the words are organized to express thoughts and concepts, is critical to effective writing, but so is proper spelling, word choice and syntax, or sentence style. Comprehension of the rules of writing will make your writing clearer and communicate your ideas more effectively than writing blindly. And once you know the rules, you'll also know how to break them for the maximum positive effect to your writing.
Breaking (violating really) the rules of writing is rampant among students today. When I taught freshman history classes, I graded more papers than I care to remember. Most of them were at least halfway decent attempts at doing the assignment and making a good grade and some were just horrible messes, but almost all of them, except the excellent papers, had problems with their grammar.
I noticed after grading hundreds of those student papers that the students struggled with using grammar properly and their choice of words, as well as their spelling and structuring their sentences. These problems even creeped into the otherwise good papers in some small fashion. It was so serious that after I graded the first round of essays in my first semester of teaching that I staged an intervention of sorts for my students. I took them through some of the problems I'd noticed in their writing.
Some were common mistakes, for example, being tripped up by they're, there and their, or affect and effect, which can be fixed by simply understanding what each word means and how it is used, then applying that knowledge every time you write. But I saw some errors that were true grammatical oddities. In the same paragraph, or worse, the same sentence, some students confused tense, number and person. Other students failed to capitalize proper nouns or they capitalized "everything that looked important." Some students went so far as to capitalize every single noun, like in German. Others confused words with similar spellings or sounds, witch and which, as well as through and thru, were prominently misused; and overall, the writing just sounded bad. So much of the writing I read was stifled and stilted, or just lifeless.
How you write, the style if not the medium, affects the reception of your message. When you make grammatical or spelling errors, whether through carelessness, apathy or ignorance, such as referring to the Presidents "Bus, Regan or Barak," then there is simply no way the reader will take you seriously. Similarly, your writing is weakened by referring to all the "things" that someone is supposed to have done, the great "affects" they had on the world, "there" continued importance in "are" world, or why they're "very unique."
I reminded my students that each of these problems can be corrected if you know what you're doing and apply yourself to the task. Ignorance, after all, is fixable. Some fixes are easy and preventative, such as knowing your spelling and grammar rules when you begin to write. At other times, such as every time you write something for publication, you'll have to proofread what you've written carefully to ensure you've used proper spelling and chosen the correct words. You can do it yourself, ask a friend or colleague or pay for a service, such as Grammarly.
The catch is that you have to know the right words, how they're spelled, how they work, what they mean, in order to become a better writer and be satisfied with the quality of work you produce. You have to know the grammatical rules in order to use correct grammar. That means reading widely and across genres, seeing how others use grammar properly, and reading books on grammar to understand the conventions of the English language. It'll take work, but it's definitely worth it to become a better writer.