One of my goals this year is to get on the podium. And I'm not referring to top 5 - to me the podium is top 3. In every workout where there are sets, I always refer to the final three sets as the podium set.
These final three sets are always the hardest for me - either because fatigue has set in or mentally I am done with the workout. I see the final three sets of a workout as some of the most important - the ability to eek just a little bit more out of them, in my mind, makes a difference. So when I reach the podium set at the end of a workout and the desire to "just complete" them is trying to take over, I think about the podium at a race and motivation to work just a bit harder to hit the target [heart rate, watts, swim time, etc.] returns. Try it next time you are in a workout and think your legs are done - you just might surprise yourself.