Sports cars have a tachometer, a gauge showing how close the motor is to melting down.

When the revs enter the red zone, performance is enhanced–for a while. Do it too much or for too long, and you’ll burn out.

In our work, there are two sorts of red zones.

Athletes know that the last 5% of their effort accounts for 100% of their success. The same is true for pianists and any endeavor where we are sorted by elite performance.

But many people work in industries where the last 5% of their effort might account for just 5% of their success. A stockbroker who stays busy cold calling clients late into the night doesn’t receive increasing rewards–they just get a little busier.

The problem with the linear reward curve is obvious–people who are driven to get just a little more repeatedly do just a little more, until they’ve broken everything they said they wanted.

If you’re going into the red zone, be clear about what the outcome is supposed to be.