English is a beautiful language

"Happy belated birthday!"
With a nod to Princess Bride and Inigo Montoya: You keep saying that phrase; I do not think it means what you think it means. There is no “belated birthday.” A birthday is a specific day, so no one can have a late birthday. If I miss someone’s birthday, the phrase is: “Belated happy birthday (wishes)!” because the wishes are belated, not the birthday.
English is a beautiful language and applying what we learned in elementary school helps us to communicate more clearly and promotes better understanding. (It also prevents expensive lawsuits, as people have gone to court when language is found to be misleading or incorrect.) The way a phrase is ordered (syntax) can alter the intended meaning. For example, this news headline:

Former Deputy Sentenced For Missing Wife's Murder

Maybe he was just busy that day and couldn’t be there for the murder?
Sometimes a typo is just a typo. I don’t think I want to be contacted by this associate:

I’ve been fortunate to be employed as a copywriter/editor/proofreader for many years and am pretty passionate about getting things right (in accordance with AP Stylebook and Merriam-Webster) before my work is published. I feel strongly that professional work should be correct. In various studies, polls and surveys, people have said that errors on business ads, websites, flyers, signs, etc., affect customer perceptions and impact the brand. Comments generally fall along the line of “If they can’t even get the spelling correct, what does that say about the quality of their other work?” Errors diminish perception about the quality of the business, they devalue the impact of the message. People have been known to lose confidence and to even quit doing business with companies because of the lack of quality in their published work.
That said, though, I’m not a “grammar Nazi” and, frankly, I find the term abhorrently insulting. If you make errors in your personal writing, it doesn’t matter to me one bit. (I do it all the time; I don’t check my personal writing with the same level of scrutiny that I do my professional work.) Sure, it helps to clarify meaning when the work is correct, but I’m usually able to figure out what you mean. I’m not a writing judge. And, by the way, why are mathematicians not called “math Nazis” or scientists not called “science Nazis?” If someone points out a math error, you thank them. But people are blasted for pointing out personal writing errors, so I just don’t do it unless someone asks for help. Even at work, if someone else makes an error on their published work, I don’t point it out unless someone specifically asks me to review their work for errors.
Some folks on Facebook have asked me to help them by posting examples of common errors so they can improve their communication. They’ve been very appreciative and find it helpful. I think people generally want to grow and evolve, to learn how to do things better, to improve themselves along life’s journey. I’m always learning new things about language usage. I’m passionate about information design—how we design information to be consumed by the user with understanding and clarity—and I feel that language is part of the discipline of information design.
I’ll end with a little nugget that, like the late birthday greeting, doesn’t mean what most people think it means:
In “ZIP code,” ZIP is an acronym for Zone Improvement Program and should always be capitalized per the United States Postal Service, which created the program. “Zip code” is incorrect. And now you’ve just learned something new!