This principle is about trusting yourself and not listening to the opinions of others to the exclusion of other information. Pretty deep for a gaming blog huh?
I'd say I'm fairly opinionated about gaming, in some respects that's a given with my starting a blog about it. Alongside that though I think I'm also open minded and not someone who will impress my opinion as factual.
The principle involved here is around taking your own counsel on things in relation to the games you play.
How you decide what game to buy next shouldn't be decided by reviews or ratings or the opinions of others including friends. These factors should educate your knowledge in making that decision yes but just because a review gives a game 3 out of 10 and someone you know says bad things about the same game (which of course might be based on a review they've read/watched rather than through, you know, playing it) doesn't mean you shouldn't choose to try it.
Knowledge is what gives you the ability to choose a game. Now if there is a reviewer who you trust as they seem to like the same games as you then that's educated information which increases the likelihood that you will enjoy that game.
Does that mean you should ignore ratings on websites such as BoardGameGeek.com? Not exactly. What it does mean though is that the people who are applying the ratings on that website might not be looking for the same thing you are. They might not play the same games that you do.
Let's choose a game that I own. Straw is a game by Alderac Entertainment - http://www.alderac.com/straw/
The game was recommended to me during the 1st Chapter by someone who works for the publisher. Initially I looked at the BoardGameGeek page for the game and decided it wasn't something I wanted to stock based on the score it was given (6.10 currently). The publisher representative offered me a demo of the game and (quite rightly as it turns out) told me that BGG is not the audience for Straw; at least not it's core audience. Straw is a game which retails at £12.99 and is a fun, simple, light hearted family friendly game. I played the demo and immediately saw that it was all of those things and knew who the target audience was.
It fits into that category of game which is usually dubbed as a "gateway game". By that it means that if someone who is new to Tabletop Games likes Straw then they might be interested in trying something a little less mainstream like Ticket To Ride or Settlers Of Catan.
Really what this boils down to is be open minded about the hobby. Remember not every game is for everyone but at the same time any game could be for you and those you play games with.