I like exploration that can benefit the player with bonus items or items that can buff the player up in some regard. ALTTP has dungeons or areas inaccessible until you find the item which is hidden somewhere in the overworld.
Majoras Mask can be beaten without collecting all the masks, Ocarina of Time can be beaten without any of the masks, extra milk containers, extra heart pieces, or the big Goron sword for example.
There's tons of examples in 3D Zelda games where extra items help the player instead of being a tool for progression. Having to scour every inch of an area hoping to get an item that lets you progress is the most unfun thing to me.
Why do I like the series? Sense of scale, the feeling of awe when you see a big or grand area, fun dungeon design, eerie or overpowering moments, evenly matched boss battles, the mask element in Majoras Mask, these are some elements I've enjoyed in the Zelda series.
