Technically, it's pretty great. Nice choreography, nice cinematography, obviously directed with a lot of verve. But (especially in the first half) I ran into a huge, huge speed bump.   I hated the main characters.   Hated them.   Hated every moment of their insufferable "special little snowflake" first world problems. I wanted to punch Ryan Gosling every time he was on screen. Emma Stone was vapid and felt like a stereotype of every single wanna-be ingenue/starlet e