So here's the deal: We know that elves don't sleep, but they do need four hours a night of "trance." This isn't the full story. An Elf can survive on four hours of trance per day, but their actual predilection is to spend close to their entire lifespan that way. Nearly every member of Elven society is drifting around with the ephemeral, zoned-out disposition of a Man frittering away his time on a rainy morning after staying awake through the previous night.
Elf life is full of post-coital cuddling and strumming forgettable ambient tunes on stringed instruments. Their villages are places of absolute serenity because none of them do anything very loudly or energetically. Even their children are ridiculously sedate. They don't have much of a capacity for hard labor but they do manage slow productivity in the form of low-intensity study and light industry. You're probably never going to see a strip mine or clear-cut field resulting from Elven effort but you will certainly see artisans produce intricate works through months or years of slow-burning whimsy and you'll note how well suited their inclinations are to the massive bonsai projects they maintain for the purpose of treetop shelter.
Elves do also have a reputation for ferocity and imperiousness. This is the inevitable result for a people who can only manage expedition through campaigns of over-exertion. Elves will, over the course of their lives, occasionally get on the warpath to achieve something important and time-limited, and they do this by snapping into their analog to long-term sleep deprivation. Every Elven emissary or adventurer you meet on a four-hour-per-day trance schedule is burning the candle at both ends and riding a form of psychotic motivation that is particular to their kind. They can keep this up for much longer and with fewer diminished capacities than a Human surviving on cat-naps, but it's uncomfortable, stressful, and leaves them feeling manic and irritable. Some extraordinary elves keep this up for decades but it's also said to be an unhealthy habit that will take years off your life. Certainly, some of the more prodigious Elves do seem a lot more severe and rough around the edges than the ones who can take it easy at home.
Shit, Elrond, stressed out much? You must be managing some kind of war effort, or something. Look at your face, you need some fucking trance.