You have to create convincing dead ends for your character to go down. Stumbling into the forward motion of a story can sometimes be more lifelike and convincing than something that moves along with no friction. People make plans but life happens and some stories forget that. If a plan went accordingly each time then what would be the source of drama?

In the beginning you set up your protagonist, but do they really snap into focus until the antagonist shows up? Would be Picard be as great without the Borg? Would Janeway? What about Kirk without Khan? Sure Shatner is pretty great, but was he ever better than when pitted against Khan?

Your obstacles are important as your heroes and the skills and qualities they bring to the game. Who would care about Endgame if Thanos didn’t convince.

And never forget, your characters need to have skin in the game.