“Worst forced minigame”
Specifying “forced” because the more optional something is the more ignorable it is.
Final Fantasy X has some truly terrible ones that are only semi-optional, though, considering you have to play them to get the celestial weapons. The lightning dodging one is just ridiculous.
But my least favorite of all is completely required; the “make Bowser sneeze” minigame in Mario and Luigi: Bowser’s Inside Story. Actually, the giant Bowser battles are pretty bad too, or at least excessively hard compared to the rest of the game.