Moving without expecting rewards both now and later

I'm a bit confused by the information I'm getting. On one hand, it's

"don't focus on the outcome, just do the task" and on the other it's

"don't expect the task to be rewarding either".

In the end you end up with no reward. Now or later. The monkey never gets his banana. This frustrates the monkey.

Is this what it means to execute a task? A calculator doesn't get a reward once it creates output. It doesn't moan when you push its buttons either. It is just a tool. Useful in some scenarios.

Is it all an attempt to decouple executive tasks from pleasure?