That line, “But I was going into Tosche Station to pick up some power converters” unintentionally become one of the most famous lines from the film. While talking to Entertainment Weekly, Mark Hamill talked about this annoying aspect of Luke’s personality and reveals why it was incorporated it into his character, saying: 

“That’s funny you mention the Tosche Station. I thought we might only be able to make the first film, because the second and third parts were predicated on how well the first one did. So I said, I’m going to have to make this as juvenile as I can so there’s room for growth. And I sort of wanted to make it sound like I had four sisters and two brothers when you’d be in the car and they’d say things like, ‘You said we could go to the mall.’ So I wanted to give that flavor.”

It makes sense that they would want to do that to give the character more room to grow and mature. Hamill goes on to admit that even he thought it was cringe-inducing and didn’t realize it would haunt him throughout the rest of his life:

“It was cringe-inducing even at the time, but I explained to George [Lucas] what I just said to you, and he said, ‘Yeah, okay, do it.’ Little did I know that it would haunt me for decades. In fact, Empire magazine said that the top Luke Skywalker moment of all five movies is that line. That’s when I knew that they didn’t know what they were talking about. I was so insulted.”

There was actually a scene in Star Wars where Luke goes to the Tosche Station, but it was cut from the film. Hamill talks about this scene and offers some insight into how Luke was treated by others at the Tosche Station:

“All of his peers ridiculed him. They call him Wormy. He’s been out in the sun too long so you know he’s not particularly popular. He sees Biggs Darklighter, who later dies on the assault of the Death Star. That’s why I turn off the targeting device, when I see my best friend die. But since it’s rendered meaningless since you hadn’t seen him, then they had [Alec] Guinness come in and say ‘Uuuuuuse the force, Luke.’ That’s when I turn off the targeting device. But what I thought was really interesting is when you see Biggs, he’s in an Imperial uniform. So Luke goes, ‘Cool!’ He has no political persuasion. It’s just, get off of Tatooine. And I thought that was important.”

In the end, those power converters he wanted so badly ended up being nothing compared to what he ended up getting himself into. Luke did end up maturing over the course of the films, but some might argue that he reverted back to whiny Luke during parts of The Last Jedi.