That you never worry about them. You don't worry whether you're doing the right thing or not, or what they're reporting about you to others. You don't worry about their approval or whether they're going to accidentally create obstacles for your work. Due to circumstances outside of everybody's control, great managers may be forced to deliver negative news and have unpleasant conversations, but there's no part of that where you feel they might be hiding something or letting you down. Great managers function seamlessly with whatever you're doing as if they were just another part of your body. They're an extension and natural part of whatever you all are doing, not a separate entity that adds complexity, drama, and stress to things.
In that sense, great managers work for you, not the other way around. Yes, they might have to fire you one day because of budget cuts or some such nonsense, but you never doubt that they spend their time working to learn from their reports and remove obstacles for them -- most times without folks having any idea what they're doing.
ADD: If you're interested in learning more, a good book on teaming and how managers/leaders fit in is "The Culture Code"
In that sense, great managers work for you, not the other way around. Yes, they might have to fire you one day because of budget cuts or some such nonsense, but you never doubt that they spend their time working to learn from their reports and remove obstacles for them -- most times without folks having any idea what they're doing.
ADD: If you're interested in learning more, a good book on teaming and how managers/leaders fit in is "The Culture Code"