Shades of Grey.
The one where Wesley steps on some grass.
The one with the Irish stereotype race.
But I still put Threshold last. The thing about a bad TNG episode is it still had a better cast/characters than Voyager, so you still got Picard being awesome, Ryker being snarky, Worf deadpanning, Data misunderstanding things for comedy effect etc....Whereas aside from the Doc Voyager didn't really have any great characters to carry those duff episodes.