The Fire Temple
Perculia:Entering the Fire Temple required specific items, like the Forest Temple–but with a more sinister twist. If you didn’t have the Red Vest on, you would eventually burn to death. You could also easily kill yourself improperly exploring the area outside of the Fire Temple, by falling into lava or executing a jump imperfectly. Acquiring the Red Vest wasn’t as complicated as winning the hookshot from Dampe, but it held sentimental value as Goron Link gives it to you as a gift.
Hamlet: I never thought the vest mechanic amounted to much. Need the red one for Fire Temple, need the blue one for Water Temple–never anything interesting about it. I guess what I’m really saying is that the whole equipment system in this game never pulls any weight (worth pointing out especially since it’s the first Zelda game where they do something like it). The only exception is Master Sword vs. Biggoron’s Sword, which is an actual decision based on the combat situation. Once you learn to manipulate the controls to instantly pull out your shield even after using the two-hander though (keep a one-handed item like Hookshot equipped, mash Hookshot and block in quick succession and you’ll block, even if you had the two-handed sword out a moment earlier), even that’s degenerate. The whole equippable-items system is bloat in this game.