Just wait till we get the Shanks vs. Luffy fight.
They're gonna stand far apart and stare at each other throwing invisible CoC beams.
It's gonna be Raizo vs. Fukurokuju II.
Shanks vs Luffy will happen just for one second. In their exclusive mind-sphere, they have already explored every maneuver possible against each other. But in each fraction of every passing attosecond, Shanks also senses that Luffy constantly create new, ever-improving G5 techniques.
When their ultimate clash explodes with unstoppable final attack of each, Shanks concludes since that moment, Luffy has finally clearly surpassed him.
So Luffy vs Shanks doesn't even physically happen, it's all within the grasp of their mindscape. Shanks says "heh...i knew this would happen."
Luffy sits down and whines all of a sudden, "Omg Shanks you should've warned me beforehand. I'm not used to doing that kinda complicated mindscape stuff."
"Gotta train yourself for Teach, Luffy. I've tracked his journey to ancient ruins. Seems like he's got other kind of games for you."
"By the way...thank you, Shanks."
"Huh? What for?"
Luffy just smiles, reminiscing about the past, and anticipating what the future will bring. At his feeling of pure inspiration and bliss, the ocean and sky brightens so warmly. It's as if the spring blooms with pure freshness, its beauty never-ending.
"Everything."