curlyfriski
Banned
I must be the only person who has no problem with it. Luffy knows that he's going to have to clash with Shanks at some point to become Pirate King, he always has. Yes, Luffy respects Shanks. But also sees him as someone to surpass. Luffy even says as much in the first chapter.
My first guess was that Shanks was the one Law was planning to take down, although I suppose it is early in the series for that to happen. Makes sense to me that Luffy would know he has to overcome Shanks, just like he has to (eventually) fight Coby.