That's a really good point.
I'm not sure if I actually understand the difference in a real world sense... but it might just be a matter of perception. If I tell myself that I want to complete my training sessions so that I'm always improving, that might be healthier than looking to be uncomfortable.

You're absolutely right!
Sprints are more important, which is why I try and do some hill sprints on my running days. I did find in my last competition that I was completely knackered. I successfully completed all the obstacles, but I was so tired that I missed out on 3rd place by 20 seconds. That was entirely due to endurance. So my hill sprints are for strength and that explosive power, and the running is for the endurance to link the series of obstacles together and to recover from each one quicker.