So this is a REALLY complicated subject, because in life you never know who is going to teach you the next great lesson or who is going to tell you something that will hurt you if you listen to it.
Gary
I used to act on quite a bit of bad advice, and have known a fair share of bullshitters, I like to think that I've developed a pretty good sense of when somebody knows what they're talking about or if they only
think they know what they're talking about. Some people will speak very confidently about things they know little about, and they're usually the ones who can really work their words and be hard to argue with.
I can tell with myself when I know something or am just voicing an opinion (like now

).
One thing that makes me doubt what somebody says is when they say it like they have something to prove, as if they're trying to persuade you, making a sale. If somebody knows what they're talking about, they don't have to sell it to you, because it's good information and can stand on its own.
I tend to have a little skepticism for everything I hear anyways, I like to check things out. Try it to see if it works, and compare it to other information sources. Of every source I come across, there's usually one point of view that makes more sense/leaves less room for doubt, that's the good one.
...Just some thoughts, this is kind of complicated.
