I won't be doing the Blacksmith's Apprentice quest again, for the reasons stated above. The one time I did it, I tried buying another forge and anvil hoping that would keep the apprentice out of my way, but she always wanted to use the forge my sim was using so it wasn't a great help.
As for quests to avoid, I've posted elsewhere about the New Gangs of Aarbyville, Assassinate approach not working. At the end of the quest your Monarch or Spy is supposed to duel the Pirate King/Queen, win, and the quest is finished - I think. Except my King duelled with her 4 times, winning every time, and the quest step to duel never went away. I haven't played the game since but it looks like my only option is to scrap the quest and lose the quest points.