Few creatures radiate the aspects of alluring physical perfection than elves
with their melodic voices and soft skin, and it did not take long for humans
to notice and begin to infatuate themselves with elven beauty. Their inherent drive encouraged many ambitious humans to romantically pursue the elder race. Fortunately for them, many elves favored humans as well, finding their passion and spontaneity intoxicating.
These unions resulted in the half-elf, a child that would inherit the genetics of their parents, often the most favorable traits, but would not inherit the social status and welcome of either. In the best situations, half-elves would be considered to favor the correct genetics for their surroundings but still have their other half as a sullen reminder that they did not belong. At the worst, they would be exiled or even hunted for being 'low blood' or 'half breed'.
Half-elves have varying degrees upon which they favor their parents, but generally their eyes and ears favor humans with softer, more rounded outlines. Their ears will end in a point, but are not as elongated as their elven heritage, and their eyes will offer a subtle, more lighter color to the iris.
They are the perfect middle ground in height - taller than humans but shorter than elves. While their skin tone is slightly more tanned (With variations in the hue depending on the environment), much like a human, their build is slightly more lithe and nimble, like their elven heritage. The males find it easier to grow facial hair than their elven cousins, though they often shave or style it rather than let it grow into an unkempt beard.
Many races, including elves and humans, find them to be beautiful, both for their physical aesthetics and general passion, exuding both empathy and ambition.
It's this same ambition that leads half-elves to strike out from their environment, often in the pursuit of a place they can call home where they'll feel loved and accepted and not alienated. Although they live longer than humans, this innate drive leads them to value items, moments, relationships, and other such pursuits, as they recognize how short lived their attachment may be.