For a while now, it seems like The CW's Fastest Man Alive has been The Dumbest Superhero Alive, having selfishly rewritten time to serve his own needs and screwing up the lives of pretty much everyone in the DC/CW universe in the process. But now, Barry may finally have learned from his mistakes. There was a lot to love about the second episode of Flash's third season: There was the Flash/Vibe team-up at the end, where Cisco used his vibe powers to throw the Rival into Barry's speeding fist; there was the arrival of Tom Felton as Julian Dorn, the delightfully acerbic co-CSI and full-time Barry Allen hater; and then there was the discovery of some of the changes that remained in the timeline after Barry's Flashpoint nonsense and Reverse-Flash's subsequent "fix".
But the real joy of the episode is that Jay Garrick stops by and tells Barry to knock off all that goddamned time travel.
After realising that Joe and Iris don't speak and Cisco hates him because he won't travel back in time to save his brother, who was killed in a car accident, Barry decides to go back in time again to try to reset the timeline again, because it's been working out so well for him so far. That's when Jay shows up and basically punches him into the '90s.
There, Jay gives him a speech about the consequences of time travel, and how once the timeline it broken it will never truly be fixed again. (It involves a coffee mug. You can watch it above.) Barry's petulance at being lectured is incredibly irritating, especially when we all know he needs it, but at the end he seems to have genuinely declared he will no longer go back in time, thus preventing more alternate reality shenanigans and fixing the show's biggest plot hole.
Yeah, I know, Barry actually learned this lesson in season two, and subsequently forgot it in time for the finale. But the episode goes out of its way to make this as declarative a statement as possible, with Barry even admitting his horrible, selfish act to the SuperSTARS (above, and boy is Cisco pissed). The fact that he has also created a new wave of metahumans to fight -- or rather, he's allowed the mysterious new villain Dr Alchemy to "rebirth" bad guys who existed in the Flashpoint timeline Barry created -- will underscore Barry's guilt and his decision for the rest of the season.
And on the bright side, it's going to be fun to find out what else Barry managed to accidentally change through his stupidity. (Turns out Barry somehow erased Diggle's daughter from existence, although she was replaced with an older boy.) If there are other changes even half as delightful as Julian constantly giving Barry Allen shit, this may well be the best of all possible timelines.