As a young boy, Luffy was bombarded with overwhelming information that he wasn't real. This broke him, and he soon developed an apathetic attitude towards everything else, believing there was no point to caring. After the death of his brother Sabo, he dropped the apathy and went to make more friends, some in other universes. But this never filled the void that left him. Now, he's decided to finally make the most of life, and do the best he can. He is finally free.