I'm no where near perfect.
With that being said I abhor the following mistakes. If you know the lyrics to "Knuck If You Buck" or "I Believe I Can Fly" or any song with Twista or Lil Jon on it you should that:
Their - Is the possessive form of they
There - (1) At or in that place; (2) To, into, or toward that place; (3) At that stage, moment, or point; (4) In that matter
They're - Contraction of they are
Your - Is the possessive form of you
You're - Contraction of you are
Are there some misspelled words that get on your nerves?