A culture where everyone has to be in the perfect 1%, or where everyone is informing on everyone, or where people are very actively competing for status and territory, is also one where nobody will show vulnerability or speak up or tell the truth, except as it seems strategic to do so.
Your "A-game" is your best, not the best in the world. Your "B-game", by extension, is something less. The way I read it, is that as long as you're doing the best work you can, it doesn't matter when you work. If you're doing less than your best work, well, you should stop.