If you make these mistakes then I automatically view you as a little less intelligent
  1. You're vs. Your
    Seriously. If you are over the age of 13 and are still making this mistake, then I will assume you are illiterate and therefore everything I say here will not offend you.
  2. They're vs. Their vs. There
    ALMOST as bad as the you're/your disaster. (It's actually just as bad, but there are three of them so I guess you could say it's a level harder.) You should be able to differentiate these before age 13 and a half.
  3. It's vs Its
    Okay, pretty inexcusable, BUT, in all honesty, I only really learned the difference about two years ago, at the ripe age of almost-20. But, I digress. Everyone should know the difference between these. Including you.
  4. Putting an apostrophe before an 's' to make things plural
    "I wish I lived in the 1950's!" "Throwback Thursday's!" No. Just, no.
  5. Saying "and I" just because it sounds correct
    "Can you take a picture of my sister and I?" "This job is important to my colleagues and I". The confusing thing to me is that these people are usually the same people who say: "me and James went to the store"
  6. For "if" and "wish", use "were"
    This is now me being picky. However, this is a free country, and I am allowed to think of someone who says "I wish this was over" or "I wish I was a doctor" as an uncultured peasant. Kidding. But I'm not kidding.
  7. Whom vs Who
    Anyone who says "whom" out loud kind of sounds like a douchebag. That being said, I will grit my teeth if you use the words interchangeably. But I will think you're stuck up if you're "whom"-ing all over the place. This is a lose-lose situation.
  8. Using "one" and then using a plural pronoun
    IF ONE USES "ONE", ONE MUST CONTINUE USING "ONE"! "If one wants to be successful, they must have self-discipline." No. No, no, no.
  9. Him and I are really good friends
    He and I are really good friends, but it's a secret between me and him.
  10. Dangling prepositions
    "This is the movie I've waited so long for!", "This is the guy I've been talking to", "There are lots of issues to focus on". Yes, I suck.