One of my favorite things about Luffy how he just… wants the people in his life to be happy? Even at the cost of his own life or safety?? It’s one of his very first actions in the series???
This kid he just befriended wants to join the Marines and inevitably become his enemy? Well why not just personally waltz over to the nearest Marine base to drop him off, at risk of being arrested and executed!!
He wants his friends to be happy and live their dreams. He supports them openly and and enthusiastically, and he truly believes in them and wants them to know it.
Part of me wonders if this is because he was raised in part by Garp, a man who tried to literally beat his hopes and dreams out of him. Who rejected everything Luffy wanted to be. Every time they spoke, Garp would violently beat him into a pulp in hopes that he would wear down Luffy’s morale enough that he’d finally agree to just being a marine.
Even Shanks, his hero, his inspiration, everything he wanted to be in life, the man who taught him the importance of standing down, the man who taught him the importance of friendship and fighting for those friends. Even Shanks said he couldn’t possibly become a pirate, let alone Pirate King. (Of course he somewhat redacted it later, but… still.)
He grew up with the people in his life that were supposed to love him telling him that he should give up what makes him happy.
And then, at the very beginning of a voyage people told Luffy he could never, should never take part in, he meets Coby, this miserable kid. A kid who is beaten and treated like shit and told he’s worth nothing. And Coby wants to be a Marine, despite thinking he could never do it. Coby confides in Luffy about this dream and suddenly this kid that was a massive wad of anxiety, who was on the edge of tears constantly and stuttered when he spoke looked genuinely happy and hopeful.
So Luffy took him to the nearest base, and even after that made sure Coby joined even if it meant losing a friend. And then when they met again, Luffy was so proud of him.