I saw this one today on a geeky website: (emphasis mine) “Calling this the database layer or the persistence layer loses site of the fact that the  model might be virtually any time of information in virtually any format.”

After re-reading this a few times, it becomes obvious that “site” should be “sight”, and “time” should be “type”.

So, the moral of the story is: Just because the spell checker doesn’t complain, doesn’t mean you are done proofreading.