Emotion management. I think this is more subtle than having a stoic front to everything. There are places/times where showing bare emotions moves the needle forward for example inspiring people, driving home a passionate point and sometimes in conflict, yes conflict, there are people who only understand emotion like anger to see the errors of their ways, for these folks reason doesn't work

And in other places/times, gulping down your emotions and being stoic is all that matters. Also no one likes a person who is inert all the time, so there's also prepping for that.