Of course, I am a Brit so like it or not I know grammar, I don't know what things are called but I know what is, and is not, correct.. But I don't really like it, nor do I approve of it :P
What niggles me most of all, is when things don't even follow the rules and when some things do, and some don't. Also, infuriating is when grammar is an art rather than exact. I am happy to be wildly creative in my use of grammar - but unfortunately where there is debate over use of punctuation and grammar that can cause difficulty with people insisting that one way is right, when several ways are equally correct.