I just watched two book reviews of the same book, Happiness Hypothesis by Jonathan Haidt. Why? Because I wanted to get the gist of it, without having to chew 300 pages plus.
But I am still interested to hear the principles, in 10 minutes instead of 10 hours... wouldn't you?
The two reviews differed vastly, because of the reviewers.
Their IQ being the same, I looked at their vibration, and the difference was there... 20 points difference.
Vibration, in one way to look at, is the height from where you look at life.
The first guy looked at the book from a height from where you can see the principles, and can allow yourself to be guided by them. That is the usefulness of principles.