And here's the second-best reason: Often, we can spend an inordinate amount of time struggling to figure out what's "right," when in fact "right" and "wrong" are actually determined by your own eye and ear.
Case in point: One of the users who responded to the post decided that since there were only two adjectives for each noun, neither of these phrases needed a comma. It should be punctuation, this person said, "shiny black hair and large twitchy ears."
This person was riffing off a previous user's post, which cited Strunk and White. And while opening a book sounds like a good plan in these situations, you'd be surprised how often it can lead to the wrong conclusion.
The user citing Strunk and White didn't realize that he was citing a completely different rule. Commas have many uses: They're used in lists, to introduce quotes, after introductory phrases and more. So while you could read that you use commas in "series of three or more terms with a single conjunction," this may not apply to your situation. Indeed, in this case, it didn't.
The above Strunk and White quote talks about how to use commas in situations such as: "I like peas, carrots, asparagus and potatoes." And that's totally different from situations such as, "He wore an obnoxious bright red tie."
That brings us to the real question at hand. Why are there no commas in "obnoxious bright red tie" when, no doubt, you'd use commas in "a tall, lean, muscular, lithe athlete"?