
That's funny! When I was in school one of my buddies used to say "I comes along and I says" instead of "I came along and said". I guess we all just form these habits of speaking over time. I get that people say "could've" or "would've" when speaking and that could sound like they said "of", but I have actually seen it typed as "could of" on several internet forums. That's when it makes me wonder.
The there's "break" and "brake" or how about "their", "there" and "they're, they very often mix those up too.