Luke in Empire is very impulsive. Abandoning his training with Yoda to race off to what is told to him to be a trap. He barely holds a candle to Vader in their first fight and upon learning that Vader is his father he decides to step off the platform to what would be certain death. In Return of the Jedi he still displays this impulsiveness by leaving his friends several times throughout the film (to go back to Yoda, To leave the landing party to rush off to Vader). Then during the climax of the film he allows himself to become emotionally compromised when Vader taunts him about his sister. It is here when Luke is channeling anger (something that leads to the dark side) that he is able to defeat Vader by just loosing all emotional control. After defeating Vader he realizes what had happen and essentially rejects the force. Tossing away his lightsaber in defiance and thus rising above the dark side. It is only later, before the Force Awakens, when he tries to re-establish the Jedi Order that he falls back into his impulsiveness. Sensing the dark side in Ben's mind he emotionally reacts by drawing his saber, something that he had to toss away in order to defeat evil, and like in RotJ he realizes his mistake trough reacting. However here it is not quick enough and only procedes to bring about the ruin of everything that he had built. Leading to the great moment in TLJ when Luke takes the lightsaber from Rey, remember the last time he saw this saber was in pain after having his hand cut off and easily defeated by Vader, who then had just revealed the worst possible news to Luke; now being held up to him by a a fresh face nobody asking him to come back and be THE Luke Skywalker. The Jedi that had failed so many in his impulsiveness. This all make his redemption at the end of the film that much better, When Luke walked out to face Kylo and then revealed that he was using force projection blew my mind. There was Luke, finally at peace with the Force, and it was amazing!