It's a lot easier for me to chase a soccer ball down a field because I have the desire to get to the ball before it goes out of bounds. It's easier for me to run faster and push harder when the finish line is right there. The way we work, we can push harder if we have a goal that is right before us. Having that soccer ball in front of me pushes me to run faster so that I could go get it. Today, I played indoor soccer with my friends and using that as interval training, since I run a lot faster when chasing after a ball compared to running because I'm wanting to run fast.
The thing is, when we have a goal that's visible, that's right in front of you, you tend to work harder towards that goal. It's easy for us to lose focus on the goals that are far ahead of us, however, when we take it step by step, we see goals that are right in front of us. Ultra runners look at the next rock and the next tree and make it their next goal. Although they are tired, using the visual goals, they are able to go further and make it all the way to the finish line.
Take each step as a goal and after accomplishing that goal, see the next one... then the next one... all the way until you reach your final goal.