No insult, no finger-pointing intended in the following.
Pharmaceutical company companies extensively research physicians' hobbies and personal interests, send attractive spokespeople to "inform" said physicians about their products over three-star michelin meals and golf games. Without exception, these physicians insist that they are immune to unethical influence.
Corporations like Coca Cola spend $10 billion a year or more on advertising campaigns with messages that college undergrads -- here I'm speaking from experience as a former instructor -- unfailingly insist they're uniquely insusceptible to.
Either these corporations are somehow recklessly burning revenue by the billions and somehow raking in unprecedented profit despite the sheer stupidity of their business practices or people are prone to maintain flattering though entirely unrealistic images of themselves. Unfortunately for us, replicated psychology experiments point to pervasive self-deception. Fortunately for us, while it's practically impossible for us to accurately monitor our own self-interest, we're marvelous at pointing it out in others. And this is the why the appearance of impropriety matters so much.
Tomes of research on the topic are out there and anyone remotely interested in cognition will encounter the experiments again and again. For those unfamiliar with it I recommend starting here:
http://www.amazon.com/dp/B006IYFCIM/?tag=neogaf0e-20