Ever want to accomplish something but been unable to because it's difficult, well just change your goal in life to something simple and do that; better yet, flood your mind with a feeling of pride for a job well done and don't bother accomplishing anything at all.

What you've just said is a perfect example of the way in which the "far" brain's intuitive modeling of minds, inaccurately predicts REAL human behavior, especially with respect to emotions.

Positive motivation actually consists of associating a positive emotion with goal completion... and this requires you to have a taste of the feeling you'll get when you complete the goal. (i.e., "Oh boy, I can almost taste that food now!").

So what actually happens when you give yourself the feeling of pride in a job well done, before the job is done, you get more motivated, not less, as long as you link that emotion to the desired future state, as compared to the current state of reality.