Do you wince when someone uses poor grammar, whether writing or speaking? Does it make you cringe when someone writes "it's" (a contraction of the two words "it is") when they mean or are referring to "its" (the possessive form)? Does it pain you to hear someone say "I should of taken the train" instead of "I should have take taken the train"? Do your eyes narrow in displeasure when you see a sign that reads: "Patrons must wipe there (or they're) feet before entering" instead of "Patrons must wipe their feet before entering"?
National Grammar Day is a day made for you, my friend.
Grammar, simply put, is the system of a language. Many like to think of it as the "rules" of a language.
I was fortunate to have teachers who were strong when it came to English Grammar during my elementary and junior high school years. They provided a solid foundation of the rules and system of correctly writing and speaking. I did not particularly care for diagramming sentences or identifying split infinitives, but learning grammar was not as difficult as math for me. I suspect it is one of those "right brain/left brain" issues. In any case, English Grammar came easier to me than other learning subjects. Though some have referred to me at times as a "Grammar Nazi", the truth is that I am constantly learning and re-learning English Grammar.
And I hope you will too.
Happy National Grammar Day! Treat our language well.