I am an English teacher.
Most people I know realize this. Therefore, most people I know understand that poor grammar irritates me and make their best attempts to avoid my biggest pet peeves.
I am by no means a Nazi about it. I will not flog you publicly for your grammatical mistakes, no matter how horrendous. I do not go about defacing signs to correct even the most shocking of mistakes. Nor do I always have perfect grammar -- especially when it comes to ending my sentences with prepositions -- so I try to cut people a little slack. My spoken grammar can become especially troublesome. When I am riled up, my editing skills cannot keep up with my mouth. Typically, however, the increased number of swear words will usually hold the listener's interest much more than my ability to avoid split infinitives.
But, so help me God, if you are a highly-educated person who still send emails with incorrect spelling and no punctuation -- emails that you have time to re-read and reconsider -- I have no respect for you. Especially when you are a highly-educated person who is in the business of educating others. Practice what you mother-effin' preach, people.
Today, someone tried to argue with me via email. It wasn't enough that the reasoning was transparent or the sequencing became muddled. Nope. It wasn't enough that this person cannot distinguish between "you're/your" or "their/there/they're". Reading also was a problem apparently as questions I did not ask were somehow deserving a nonsensical answer. What really blew my mind was when the idiot tried to tell me that I didn't make any "since".
Here's a tip. If you're going to argue with me, do it in person. Face-to-face is my weak point. My emotions get the best of me. I get flustered. I am usually so angry that I cannot think straight. I will eventually give up just as a way to get you out of my face. You should not argue with me in writing, and if you choose to do so, use your best grammar. Because once I see some jacked-up language skills, I know that I am going to annihilate you. By sending me your electronic bullshit, I have time to take a deep breath, sort out my emotions, and craft a carefully worded, delightfully wicked, stinging response. I also have time to revise just so I can make it hurt a little more. And I will never give up. Repeat. Never.
It's worse than bringing a knife to a gunfight. You might as well be armed with a fucking popsicle stick.