6. Luke and R2's Plan
The Moment: Just as Luke is about to be executed via a thousand-year digestion in the Sarlacc Pit, he signals R2 who launches his smuggled-in lightsaber for him to catch and then use as a weapon to escape.
Why it's Dumb: Let's face it, this scene is epic, but on closer inspection the plan is basically nonsensical; for it to happen, Luke would have to had to communicated it with R2 before he delivers him purposefully as a good faith gift to Jabba. He would have to have known his execution would be at the Sarlacc pit (which is unlikely given that he apparently had no idea about the Rancor pit), made the assumption that R2 wouldn't be searched, and known R2 would be positioned to launch the weapon at the precise moment of execution, even though it is perfectly possible Jabba could have him stashed away somewhere.