A Good Night’s Sleep
Dungeons & Dragons is pretty phenomenally generic. By design really. But one of the few divergences is the elven habit of not sleeping. Instead, elves enter a meditative state–or trance–for four hours. (Although, I personally find “trance” to be a little bland and prefer the term “reverie”.)
What is most interesting is how little this major change affects portrayals of elves. They don’t sleep. Ever. So they’d view other races as extremely lazy, just wasting away a sixth of the day in beds. Which leads to another though: elven homes wouldn’t have beds. Would they even have bedrooms? Without the need for a quiet space to sleep, they might lack personal rooms and just store possessions on shelving or closets. Would they even have sizable home? Cooking and socializing can occur outside just as easily, so houses might be little more than storage areas for perishables. Sleep is often equated with death. Elves not only don’t sleep but also live for several hundred years, so death might be terrifying and even more unknown to them. Seeing other races sleep might be extremely unnerving, a reminder of immortality and the unknown. Possibly even more unnerving that some immortal guy sitting beside your bedroom and staring at empty space for four hours.