I'm a bit of a grammar geek. Actually, when my hypothetical kids have kids, I think I'll go by "Grammar". The whole thing--not "GRAM" for short, as it's hackneyed and I measure in ounces. They will be chastised accordingly for shortening the name, or not pronouncing it with a capital "G." They will be born brilliant, so this lesson should only have to be taught once, if at all.
When someone utters a word in text or speech that is used incorrectly, I get tense. Puns always intended. I am a little less weirded out by misplaced commas, and that is probably because it is my weakest word link. I dole out commas like little cups on the sidelines of the marathon for my run-on sentences.
I've tried to understand where this 'irked' feeling comes from. I think it might be from several sources. Firstly, the urge to correct them is overwhelming and is consequently followed by an eye-roll, whether deserved or not. I would like to point out whether the eye roll is deserved is dependent upon the probability that they would make the same mistake again. If it might recur in the future, you did them a favor, and an eye-roll is unwarranted. Secondly, it's completely unpopular to care about grammar in this modern day when asynchronous communication is commonplace and fired-off quickly with auto-correct. Auto-correct, as we all know is not fool-proof. This does not affect my ability to be aware of the errors out there. I simply choose my correction battles to be fought only with a valiant few who might respect and honor the literary shift.