"Is my partner having a good time": Make your partners look good. That is usually a good idea in any team.
"Find the earliest end". That would mean don't ever maintain an old product because there's nothing interesting in it...
"Yes and" principle: you accept the ideas that your fellow players introduced and build on top of them. For example, "Backend moved their data store to a novel distributed document store they read about on Twitter -- Yes, And we'll let the frontend run in a JS-emulated Browser-in-a-Browser!". I see that being applied, but I'm not sure it's good advice.