Flashbacks are boring. Often, they use stock footage and make it seem like the story's on hold. A not-so-recent subversion of the typical flashback is to have the flashbackee be an observer. He walks around and watches his younger self, "Was I really like that?" Perhaps another person is in there with him, berating him for a pathetic life choice or showing him what he has to live for. Makes for an interesting sequence. Examples of Pensieve Flashback include: