Six Years of Struggle for Three Hours of Glory

The idea of running a marathon in under 3 hours has inspired me ever since I started running. Next to "just finishing" and the 4-hour barrier, it is the biggest goal for any ambitious amateur runner and the biggest motivation to train for a marathon in the first place.

But why are we so in love with these particular time limits? After all, they're just numbers, and a 3:03 marathon is, from a purely athletic standpoint, exactly the same as a 2:57 marathon. So why should we wholeheartedly commit to...