Hearing D.C. Fontana say that "The Doomsday Machine" was her least-favorite episode (!) got me to thinking: What other precious episodes aren't necessarily beloved by everyone? I'll start, with "A Piece of the Action." I don't find it amusing or even very interesting. To me, it feels like a 30-minute sitcom stretched to fill an hour-long timeslot. Self-consciously cute. And it's part of the too-many-parallel-worlds syndrome that affected the second season in particular. Others?