As requested by @amandalaurino
  1. The opening credits
    Mostly for the filth, farts, and Smash Mouth
  2. The earwax candlelight dinner
  3. "And in the morning, I'm making WAFFLES"
    Literally everyone's favourite line (but especially in the case of drunk people, it seems)
  4. The way Shrek says "and the squatters" when he is trying to negotiate his swamp back from Lord Farquaad
  5. The ogre-onion-layer discussion
    Parfaits may be the most delicious thing on the whole damn planet
  6. The travel montage to Princess Fiona's castle
    The animation is GORGEOUS
  7. "It's Brimstone"
  8. That winning smile Shrek gives after Princess Fiona forces him to take off his helmet and reveal his true colours
  9. Donkey's quest for blue flowers with red thorns
    And the discovery of his colour-blindness
  10. The heart to heart between Shrek and Donkey while viewing constellations
    And when Donkey inquires about the moon
  11. The way Princess Fiona says "no kidding" while eating her weed rat on a stick
  12. The Hallelujah montage
  13. "Mother Fletcher! He already said it!"
  14. At the very end, when they're all singing "I'm A Believer", there's an aerial view of all the characters and the Big Bad Wolf gets me every time!!!
    I believe.