Usually, when we use the phrase "Don't shoot the messenger", we do it in the interest of pointing out that the bearer of bad news isn't in any way responsible for the bad news itself.

But there's another reason that a lot of us shoot the messenger, and it has nothing to do with the news itself. When someone presents us with an idea, we assess the idea and ultimately reach a decision that is tainted with our own perception of the messenger himself. We frame what people tell us with our own opinion of those people, and that leads to our conclusion.

It doesn't matter if Suze Orman, Jim Cramer, and Charles Schwab give you exactly the same financial advice in exactly the same words. If you like one of them but not the other two, you'll only listen to the advice coming from the one you like, based on your own personal preference and comfort level. Or maybe you hate all three of those people I mentioned because you think they're all profiteering scammers, but if a family member gave you the same advice, you'd listen to the family member and write off the advice of the other three.

Who the messenger is (to us) matters a great deal.

From this, you could draw that if you want to influence those around you, you need to be careful to frame yourself in the eyes of others, and how other people perceive you. I think the real lesson is that we need to listen carefully no matter who is talking. Great ideas and advice are everywhere, and they're generally free. Ignoring them because you don't like the messenger is shooting yourself in the foot.