If you question the last trait, ask yourself how many times you, as a sales professional, needed to help your client make a decision. Or how many times you had to deal with buyer's remorse or had to help your customer understand that the product they are considering really will help them in their personal or professional lives.
If I had to design a college course schedule for a degree in "Sales," there would certainly be a few psychology courses on the curriculum. But my psychology courses wouldn't include dream analysis or how to resolve issues with your parents. They would include courses that discuss why people do what they do and how sales people can assist people with decision making.
I am not talking about using "mind tricks" or any psycho-babble "I'm Okay, You're Okay stuff. But instead, how can sales professionals help customers to more clearly see their way through a buying cycle.