we were told to be creative, so here's a stretch. after competing in a bike race earlier today (see above), i realized something even though i had know it for awhile. endorphines and adrenaline are really helpful. by all means, i should have been exhausted half way through the race. it was 18 miles, which doesn't sound like a lot, but keep in mind that this was all off-road, with some long nasty climbs and rocky descents, on a bike with only one gear (that was by choice, though).
what made me realize what i did was because of riding the race course last weekend with some other teammates, for about two hours. granted we weren't going at race speed, but i was more tired after that than i was after the race today (after hacking up some dust and drinking mass amounts of water). this is a rather common thing for many types of competition as well, so maybe you can relate.
okay, why is this a phenomenon? well i'll tell you. first off, it meets the criteria layed down by ozayr. the thing is fatigue, the framework is the bike race (or any other competition, for that matter), and the clockwork is a stopwatch and a start/finish line in this case. the adreniline kicks in when the gun goes off, and lasts for awhile. that gets you going, often faster than your muscles would like. then, after awhile, your body starts producing endorphines, which cheer you (and your muscles) up, move your mind away from the muscle pain and towards how much fun you're having, and thus keeps you going. so instead of thinking of dropping out, you keep racing, and have more fun.
this is expressed as: fun+ fun = more fun