Advice is a funny thing: frequently offered, commonly ignored, often wrong.
For example, even as recently as the 19th century, if you were unfortunate enough to find yourself in need of an operation, you may have been slightly dismayed to discover that your surgeon didn't believe it necessary to wash his hands before slicing you from top to toe. Sadly, you would have been all too aware of his shoddy hygiene regime, because anaesthetic at that time consisted of enduring the pain, getting very drunk, or arranging for someone to batter you about the head with a large halibut. I imagine you would have been even more disappointed when the parts of your body that were supposed to be fixed instead turned gangrenous. And then dropped off.
All of this because a few surgeons took some bad advice. I mean, they knew that germs caused disease, but it took a surprising amount of time for these chaps to come to the conclusion that dirty hands may in fact be laden with germs, and that offloading these directly onto a patient's spleen might not be desirable. Eventually however, a handful of doctors started offering sensible advice on the use of things like soap and disinfectant, and these new fangled methods slowly became accepted throughout the profession.
On the big screen, the 19th century doctor is usually portrayed as old, drunk, cynical, indifferent, or all of the above. He examines his patient's malady with a professionalism laced with scorn before prescribing a few leeches, to be applied to the testicles, daily.
Contrary to the televisual fiction, these doctors probably didn't take sadistic pleasure in inflicting abject misery and suffering upon their patients. At least, not any more than the modern doctor with the glint in his eye and the very sharp needle and the "this may hurt a bit" reassurance. They were probably mostly a well-meaning bunch. But, operating with out-dated or flawed knowledge, they didn't stand much chance of success.
Medical practitioners in ancient Egypt were even worse. They believed that the best cure for open wounds was in fact a poultice made from human faeces. Hmmmmm.
And this obviously brings us to search engine optimisation. Even today I still hear of "web professionals" offering advice to clients on the importance of META Keywords to search engine success. This despite the fact that for years none of the major search engines has had the slightest interest in allowing you, the website owner, to tell them how to index your website. They already tried this method out, and thanks to Johnny Pornmonger stuffing his websites full of non-relevant, everyday keywords, they found it didn't really work that well. Instead the search engines have invested millions in creating systems that can index a website automatically based upon its content. These systems can do this to a very high degree of accuracy. In fact it is now possible to search the interweb for ordinary things and not be presented with a set of results that would make a sailor blush.
META Keywords are, to all intents and purposes, obsolete.
Logically then, if you follow bad advice and waste your time messing around with META Keyword tags, you will develop gangrenous sores, an unhealthy interest in turds and an Internet browsing history that needs regular clearing. I guarantee this will impede your business progress.