Bart's Blackboard gag opening in The Simpsons' is an iconic scene, and every scene is different. And in every message, while being funny, is a also a life lesson buried somewhere there. Here are some of them we've learned so far. Check them out:

1. On excuses:


2. On respect:


3. On cutting corners:


4. On hygiene:


5. On science:


6. On education:


7. On getting favors done:


8. On showing off:


9. On assigning blame:


10. On manners:


11. On the Internet:


12. On making fun of history:


13. On playing with your food:


14. On discipline:


15. On creating excuses:


16. On bullying:


17. On religion:


18. On the use of proper grammar:


19. On reading:


20. On subliminal messages:


21. On playing pranks:


22. On dealing with loss:


23. On telling lies: