In a writing partnership, you want a certain amount of creative conflict. If you agree with each other all the time, who needs two of you? You need to be willing to criticize and shoot down each other's ideas. To say, in Denis McGrath's old catchphrase, "Here's why I hate that."
This is hard to learn. (Unless you are from New York, in which case you have to learn when to shut up). In companies, most people often feel they can't voice their concerns. The whistleblower is the odd man out. Or look at American politics, where almost no current politician dares criticize the country's utterly insane drugs policy.
In a creative partnership, you want different points of view to clash.
On CHARLIE JADE, Sean Carley, aside from being a very fine writer, was the guy in the writing room who would call shenanigans on Denis and me when we came up with something he didn't believe.
After all, if someone in the room doesn't believe it, what are the odds that the audience will?
What makes creative conflict useful is restraint. You have to agree on the underlying premise. I've got notes back on my writing where the analyst did not buy into the basic premise of the material. That kind of note is not constructive. (It may be accurate, just not constructive.)
You also have to agree on what you're critiquing. If you're working on our premise, you critique your premise. If you're working on your outline, you critique the beats, and maybe you critique the premise if the beats cannot be made to work. If you're working on pages, you should no longer be critiquing the premise. A creative partner who keeps going back to the drawing board will hold you back. This is particularly true on a TV show, where you just don't have time. But at a certain point you just have to have faith that your premise will hold up.
It's crucial because about 40% into anything, you'll probably start to question whether the idea has any merit. You'll also question whether you're capable of writing it. Or writing anything. You will possibly get the idea that you have lost any talent you had, if indeed you ever really had any. That's why I call 40% in "The Sucky Point
Criticism is essential to making anything good. But just like heat applied to steel in the forge, what makes it productive is focusing it on the right part of the material at the right time.