Any time Link can attack Cuccos...only to have an endless swarm of killer Cuccoos chase after him in revenge.
Late in "The Missing Link," Ganon states that Zelda is able to see Link's non-corporeal form due to The Power of Love. Both Link and Zelda are in earshot of this. Zelda profusely denies this to Link...
Link: Yes you do!! Yes you do!! *sings* That's why you can seeeee meeeee!!!! *stands up on a ledge to proclaim the glorious news to the rest of Level-9*
The entirety of "The Moblins Are Revolting," where Ganon's army is so incompetent they defeat themselves.
Even the beginning, where they come close to stealing the Triforce of Wisdom as Link reads a comic book, and they defeat themselves easily.
Link: Boy, I'm good.
Link telling the Moblin leader that their plan is the stupidest plan Ganon ever conceived, only to be told that the monsters thought it up themselves.
The Moblin leader tells another Moblin to be careful with the magic staff and to not drop it. When the other Moblin asks him to repeat the last part of the order, he yells "Drop it, stupid!" causing the other Moblin to do just that. The Moblin leader, hearing the staff break, does a Face Palm and muses that now he knows how Ganon feels.
Ganon's reaction when he is pushed into the Bottomless Pit while trapped inside a bubble.
Link and Zelda are running when Zelda stops at the edge of a rather high tower. Link keeps running and bumps into her from behind, knocking them both over the edge. They're both unharmed, but Link gives this line afterwards:
Ganon falling into his own trap in "He Also Serves" ends up as this due to the sheer amount of Epic Fail involved. After spending the entire story shapeshifting into various characters to try and get Link to leave North Palace, Link realizes that it's Ganon and has the gates sealed to keep him trapped inside. Ganon, in a desperate ploy to escape, turns himself into Link and rescinds the order to the watchman. Only he forgets to change forms again after leaving and his minions are none the wiser when they spring the trap.