I once read a short story in the Realms of Fantasy magazine that offered an eplanation on this.
In that story, during the Dark Ages, humans, dwarves, elves and centaurs shared Earth. But humans were the only magic-wielders. An escalation of the magic arms-race obliterated humans, leaving the non-magic races to carry on.
Cue in a world that looks like our own (cars, guns and whatnot), but populated ONLY by elves, dwarves and centaurs, without any humans. The main characters of the story were one of each race (male elf, male dwarf, female centaur), bent on doing some dragon-hunting for a profit (on a SUV, bearing firearms and sniper rifles).
Ok, back to the point:
The elf explains to the dwarf that elves take a LONG time to learne their lessons because, being overly chaotic, they can't divorce an event from its lesson. They only understand the "lesson" of an event after they have forgotten the particulars of said event and then looking at the big picture. Before that, they are too focused on grief, joy or whatever emotion the event brought them. And they take as long as a human to forget something, so while a human might learn his lesson overnight, an elf will take about five-ten years to be able to see the same event in the same light, and draw some lesson out of it.
