You should probably go if..
  1. Your teacher only grades you on your participation grade instead of anything you've actually done in class
  2. When you don't get any of your test grades or assignments back to know how you're doing
  3. If the final is coming up and you have no idea what will be on it
    Did we learn ANYTHING?!
  4. If you only have to sit through two ten minute presentations and get to leave early
  5. If you can casually just sit in class making lists instead of listening