There are no good or bad situations. No great or terrible sales calls. No wonderful or destructive conversations.
Just what happened, what you learned, and an experience you can use in the future.
What benefits does this have, and why is it useful?
Emotional detachment -- you won't get too high when it goes well or two low if it doesn't. Because all you're doing is learning.
The outcomes don't control you -- you're just using the situation to learn, remember? So you gain no matter what happens.
The people involved don't matter so much -- you can't control other people anyway, can you? You probably know that well if you think to your past experience. All you're doing is observing people/situations and learning from them -- so again, you gain no matter what happens.
Emotional control: The #1 element of power for any human being. Everything in life involves a situation and people -- so when they don't control your emotions, you're 85% of the way to power.