Every One Piece fan knows that the straw hat holds much significance in this grand story of seeking freedom. Long ago, this ...

The best solution to the mystery might be present from the very first ... freedom. Luffy's Straw Hat is more than an accessory—it’s a symbol of inherited will, passed from Roger to Shanks ...

When Roger fought Oden and later on, Whitebeard, he told them his deal dream as well, and it was quite clear for the fans to see that this was directly paralleled to Luffy's dream reveal.