When people talk about appealing to the lowest common denominator, that’s a maths metaphor for producing rubbish in pursuit of mass appeal, but which kind is it? I think it’s used for both. It shouldn’t be. It makes perfect sense to describe what the lazy group is doing, but we should say the group that regrets having to dumb down is appealing to the highest common factor. This pedant agrees with me that ‘lowest common denominator’ is often used when ‘highest common factor’ makes much more sense, but doesn’t acknowledge a role for LCD at all. But there is one. (I'll leave it as an exercise for the reader to work out which of his examples should have been which.) The distinction’s important, because one accusation is more scathing than the other. So let’s all start making the distinction correctly, because it’s unfair not to, and it’s really neat.
While I’m on the subject, people often say they don’t want to do something to mean that they want not to do it. I hardly ever hear (other) people saying ‘want not to’. But we all distinguish between ‘try not to’ and ‘not try to’, and the want not to/not want to distinction is exactly parallel. If you can understand one you can understand both, and as far as I can see they're equally useful. So let’s all start making that distinction as well.