It seems appropriate to start with something from David Milch - the screenwriter behind 'Deadwood' (as well as 'Luck' and 'NYPD Blue') as Milch is the reason I really became fascinated with the craft. Deadwood is truly a masterpiece of TV writing, more so because apparently Milch dictated each episode lying on his back in a trailer, the night before shooting. Whether or not this story is apocryphal the fact that I don't doubt it says a lot about the man.
Here's Milch's take on Convention:
"As I get older, I become less and less patient with convention. A convention is the set of assumptions in a story which are taken as given, rather than tested by the action."