I have seen on T-Shirts, heard from others, been reminded of it many times---that people in New York believe people in Los Angeles are not so bright.
One, this cannot be proven exactly, though, anecdotally, it can be witnessed.
But more importantly, it is easy to appear intelligent when you are looking backward and making judgments. New York is a backward looking town. Los Angeles looks forward and when you are jumping into the unknown, into the future, organizing a plan of attack using critical analysis often mucks everything up.
It would be wise for New Yorkers to begin to understand that anything that has already happened has actually already happened and any opinions about that are opinions about that. Fun fodder for the ambitious mind. But not necessarily new.