Worst one is the Jotun trading one in Wayfarer Foothills.
I must be the only person who actually liked that one, and the ludicrousness of the situation: literally using the Jotun's idiocy against them. It never takes me more than a few minutes to complete, less time than killing things because of the snowball effect of their bad trading habits.
I think non-combat hearts add a lot of flavour to the game, but since the game is overly focused on combat uber alles, I do see how it can clash with the 'go go now now' mentality the game kind of fosters in its userbase.
Still, I'd take a thousand Jotun quests, over the literal hundreds of banal fetchquests I've done in the last few days in FFXIV. I dig the game, but there is one quest that really epitomized the insanity of some of the quests in the game: you walk up to a woman who has a quest marker above her head. In talking to her, you startle her, making her drop all her gil. She gets upset and tells you to to pick it all up. You run around hitting action on a bunch of 'gil dropped' piles that spawned. Talk to her again, to give the gil back. Doot de doo, experience points, and some money.
You only talk to her because she had a quest marker, so she becomes a fetchquest by talking to her... it's like an existential quandary.
While the hearts aren't perfect, and many of them could do with having their rougher edges smoothed, I do prefer the heart system infinitely more than doing the Errand Boy Loop Of Lame going from ! to ! to ! and then !, all so that you can deliver a letter from one person to another, who is standing like five feet away.
What time?