This is a subject that really grabs my attention.  It's so frustrating to read emails or comments or blogs with so many misspelled words, because I want to edit them and send them back!  People don't seem to know the difference between to and too, your and you're, or they're, their and there.  It isn't rocket science. You just have to think before you write, or use spellcheck if you're not sure.   

It's also annoying when to be in a conversation with someone or hear someone on TV who is educated, professional and accomplished who will say something like: 'how long did you live there for?' or 'where did you go to?'  Oddly enough, I never paid much attention to those sorts of things until a few years ago.  I don't know what happened to make me more aware of it, but whatever it was it's part of me now.  Don't get me wrong, I know I make mistakes sometimes.   I just try as best I can to keep a mental eye on what I say and write. 

Oh, one more thing:  people who incorrectly pluralize words such as 'mother-in-law'.  People tend to put the 's' at the end of the word instead of where it should be...at the end of 'mother'.  I've even heard Dr. Phil get that wrong!

I suppose in the grand scheme of life these things are pretty trivial, but they bother me anyway.