It really doesn't bother me much unless it's something like what you mentioned about writing for business. I know that a lot of people have a hard time spelling just like I have a hard time with numbers and advanced math. I think people see more bad grammar and spelling nowadays because of the internet. In the past, if you were a bad speller/writer, you would just avoid doing things where that would be revealed. On the internet, most people communicate through writing, at least for now.