Dunno if I'd consider it the worst, but having to talk to the king and/or priests in Dragon Quest is tedious. I mean, yeah, it's a series' staple by now and the only reason people seem to tolerate it is because of tradition I guess. Honestly, having to trek or warp across the map to the nearest town to save is a dicey enough prospect, but why does every save session have to be this ridiculously drawn out song and dance with two or three confirmation dialogs and six or seven lines of text???
Just "confess" and be done with it already!!!