Just for the record, I totally know the difference between their, they're, and there, between it's and its, between night and knight! My problem is that my fingers don't know the difference. I'm a really fast typist, thanks to Mr. Berkman, back at Hartford High School, and I have verified that there is a direct link between my brain and my fingers. I can type someone else's text (as I did often in college), sing a song on the radio, and think about something totally different, all at the same time. Sometimes I find myself reading books to my kids, and they're sitting there in rapt attention and I have no idea what I just read. It's a strange thing.
Although I rarely write long-hand anymore, when I do, it's a bit of a disaster. I often write the word "five" as "5ive", I often add the last letter of the last word to the beginning of the next word, and when typing a more unusual word that begins the same as one I type often, my fingers often type the more common word instead. It's as if they have a mind of their own. And they can't keep up with my thoughts though they do the best they can.
Thank goodness for editing and editors!
So, if you ever find one of those typos in my writing, please do tell me about them. I hate it when they slip by. But I swear, it's not because I don't know. It's my fingers' fault.