You know fungal feeding is that quest during the Icecrown event where you have to kill ghouls and abominations near the mushrooms, which will give the mushroom stacks, and then when you kill the mushroom, you get as many quest items from the mushroom as it had stacks.
Now my initial reaction to that was "that's one of the best quests they have ever done" because it is so different from any other quest in the game. I don't think there is any like that. It's a nice change from the typical kill and fetch quests.
Of course that was quickly followed by "holy shit, players are too stupid to do this". Since many of them don't seem to know how to do the quest, it often ends with you trying to kill a mob near the mushroom, and them killing the mushroom before it has any stacks, so you get no quests items. Neither you, nor the guy that ruined it for you.
Now that's a bit inconvenient and requires you to approach the quest a bit differently, like go around collecting mushroom from the ground and keeping an eye out for mushrooms that have stacks on them.
But I'd still maintain that it's one of the best quests in the game. And I'd even say that it's not the player's fault this quest can be a pain in the ass. Because while players probably approach this quest in a wrong way, because they haven't even read the quest text, I'm not gonna pin it on them.
See, Blizzard has cultivated this sort of playerbase. When they integrated quest helper addons into the game in Wrath, they basically told people that they didn't have to read quest text anymore. You'll be able to see on the map where you have to go.
So when a player in 2020 picks up a quest that says "collect 20 mushrooms" and the area is marked on the map, of course he just flies there, looks out for mushrooms and then kills them in the hope of looting his quest items. He might even figure "well this one didn't drop any, but the other one dropped 2, so I guess it's not a 100% drop chance". Why would this player even consider that there is a twist to the quest and that he has to read the quest text in order to understand how the quest actually works?
Players have been trained for over a decade to not approach the game like that. What Blizzard now has to do is to not view this as a failed experiment and realize that they need to train the players anew, so they know what to expect when faced with quests like these and how to handle them. It can be a long process, but that's the way it has to be. You can't undo the conditioning of over a decade overnight. So quests should have more gimmicks like these and slowly replace the typical fetch and kill quests.