When we do better than what's expected of us, we cause delight. We exceed expectations.

Over time, this gets normalised and we will have to do even better to exceed expectations.

This is what happens when we get promoted. What we would previously do to exceed expectations is now something we need to do just to meet expectations. So we do more.

Upward spiral.

When we do just what's expected of us and nothing more, we might think we are meeting expectations. We are, but only temporarily.

Because there are people around us that are exceeding expectations, and raising expectations at the same time. 

So, we have to do better just to continue to meet expectations.

Otherwise, we find ourselves in a downward spiral.

Either way, the only acceptable way forward is to continue to do better.