Move the damn product.
It's a line I use in my talks a lot.
I say that the ads of yesteryear weren't so good because they were pretty, or funny, or because their layouts were innovative. They were good because they moved the damn product.
That's the measure of a good ad. That, and nothing else.
I often find myself watching TV spots and thinking, "it's funny, but it won't move the product." Because those are separate and often unrelated points.
The funniest ad in the world can be a failure. The least funny, a success.
Does that mean that entertainment has no part in advertising? Far from it. The best ads are often entertaining. It's just that the worst ads can be entertaining, too.
Knowing the difference is what matters.