So there was that time when I told 500 geniuses to stop being so mentally lazy.

I was the opening keynoter for the annual convention of Mensa, the high IQ society. [Full disclosure: I’m also a member. I’m pretty sure I got in under some sort of Affirmative Action program.]

The reaction was, shall we say, mixed.

But I stand by my statement.

Now let’s be clear: I wasn’t accusing these people of not having brainpower. I was accusing them of not using their brainpower to the fullest. And why aren’t they using their brainpower to the fullest?

Because they don’t have to. They discovered early on that “brain work” was easy for them. That their “C” work was better than most people’s “A” work. That they could coast. They could coast through high school. They could coast through college. And many of them (there are exceptions, of course) are still coasting.

This is not a situation that is exclusive to Mensans. You see it anywhere you see accomplished people: business, the arts, sports. I’m not talking about the household names; those are the ones who chose not to coast. I’m talking about the people who never became household names — but could have. The people who chose to get by with “C” work, because they could.

Are you one of them?

If you are one of these people — the super-accomplished “coasters” — then you’re missing out on a huge opportunity — and a huge obligation.

It’s my assertion — and one that I shared with those 500 Mensans — that by coasting through life, by settling for “C” work, accomplished people are depriving their families, their communities, their businesses, their world and, perhaps most important, themselves, of their full potential.

Let’s take you, for example. Look at how far you’ve come, and how much you’ve achieved! Imagine, though, where you could be if, instead of “C” work, you’d chosen to do even “B” work. And what kind of a difference could you make with your “A” work?

Look, I’m not saying you’re lazy. Maybe you are, maybe you’re not. What I am saying is that there’s probably some untapped potential in you. That whatever the level of your game right now, you can take it up a notch. Here’s how.

Whatever it is that you do, whatever your work is, ask yourself this question:

How can I do it 10% better?

Just 10%. You can do that, right? 10%. That the difference between a C and a B. Between a B and an A. It can even be the difference between “anonymous” and “household name.”

Ultimately, for an accomplished person like yourself, it comes down to a simple choice:

Do you want to coast through life? Or do you want to give it your all, and see what kind of a difference you could really make?