There are few things more hit or miss than flashback episodes. At their best, they feel like dramatically enriching detours into the past. At their worst, they come across as nothing but filler meant to pad out their respective seasons. Whether it's written well or not, though, a flashback episode almost always manages to grind a show's narrative momentum to a complete, often frustrating halt. That's why it's important that TV creators not only use them sparingly, but make sure that they communicate the narratively necessary reason for each.
