It was difficult to know whether to feel enthusiastic about tonight’s Flash. Sure, the prospect of Barry Allen jumping forward in time to visit the Central City of 2025 was exciting. But at the same time, pretty much every tragedy in Season 3 has stemmed from Barry’s boneheaded decision to abuse his powers and create the alternate reality that is Flashpoint. Was “The Once and Future Flash” going to be just one more example of Barry doing something stupid and then feeling miserable about it afterward? But as it turned out, this episode managed to bring a little light into Barry’s life even as it showed how dark things could get should he fail to save Iris’ life.