Thomas' Train Syndrome

When you travel so far / make so much progress doing something but you don't realize you forgot something utmost necessary, until way later on when it's too late. Named after the episode "Thomas' Train" from Thomas the Tank Engine & Friends, where the titular character did not realize he was not coupled to the train he thought he was pulling.

Actor: *finishing his stunt for a film* Hey Jeff! Did you see me drive all the way down San Francisco's hills in a school bus, and crash the oil tanker trailer all in one POV take on my GoPro? You've gotta see the end result! I wanna see it too!
Assistant director: Uh, Bill, you left a little too fast. I think now's a bad time to tell you we forgot to put the SD card in your GoPro. Looks like a bad example of Thomas' Train Syndrome. You just blew our budget now that we lost both of our only trucks.