These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Surprise Difficulty: The veteran Zelda gamer should have little to no difficulty conquering the dungeons and their respective bosses, until the final boss Vaati. He has multiple forms with unique attacks that all hit like a tank. Needless to say, without a strategy guide, you're going to die a few times trying to work out each form's weakness to which item.
That One Sidequest: The cucco game. The cuccos you must find only appear when you start the game, idiot villagers will always get in your way and stall you, and there's very little time to complete the challenge even if you know exactly where the cuccos are.
Not to mention some of them are on roofs and unreachable.