Bad dreams are a gateway to evil
Mark Hamill, the legendary actor who voiced The Joker in the Batman cartoon (oh, and he played Luke Skywalker), was pretty vocal about his distaste of the trilogy sequel. He used every spare moment to voice his thoughts on social media regarding how the films’ producers totally ruined a good thing.
One thing that everybody agrees with is how ridiculous it was for Luke to try to kill Ben. If you haven’t seen the movies, basically, Ben has a bad dream about turning to the Dark Side. Dreams don’t really mean anything, but Luke wasn’t going to risk it. Bad dreams = bad person, apparently.